Biogas is a kind of regenerable energy which is inexpensive and friendly to the environment, but the potential ofbiogas is difficult to develop fully in China, for most biogas have badly qualities and the utilization ...Biogas is a kind of regenerable energy which is inexpensive and friendly to the environment, but the potential ofbiogas is difficult to develop fully in China, for most biogas have badly qualities and the utilization of it is monotonous. The suitable operation term about biogas upgrading by pressurized water scrubbing was researched through the orthogonal test in this study. Two sorts of scrubber packing included the random multidimensional hollow sphere packing and the structured screen packing were also used, and the effects of experiment factors included packing, water temperature, gas flow speed, water flow speed and washing pressure were studied. The results showed that better effect was got when the screen structured packing was used; all the five test factors affected the processing significantly in the arrange as before and had better and better significant effects.展开更多
The co-removal of CO_(2)while removing SO_(2)and NOxfrom industrial flue gas has great potential of carbon emission reduction but related research is lacking.In this study,a wet scrubbing process with various urea sol...The co-removal of CO_(2)while removing SO_(2)and NOxfrom industrial flue gas has great potential of carbon emission reduction but related research is lacking.In this study,a wet scrubbing process with various urea solutions for desulfurization and denitrification was explored for the possibility of CO_(2)absorption.The results showed that the urea-additive solutions were efficient for NOxand SO_(2)abatement,but delivered<10%CO_(2)absorption efficiency.The addition of Ca(OH)_(2)dramatically enhanced the CO_(2)absorption,remained the desulfurization efficiency,unfortunately restricted the denitrification efficiency.Among various operating parameters,pH of solution played a determining role during the absorption.The contradictory pH demands of CO_(2)absorption and denitrification were observed and discussed in detail.A higher pH of solution than 10 was favorable for CO_(2)absorption,while the oxidizing of NO to NO_(2),NO_(2)^(-)or NO_(3)^(-)by NaClO_(2)was inhibited in this condition.When7<pH<10,it was favorable for the conversion and absorption of NO and NOx.However,the conversion of HCO_(3)^(-)to CO_(3)^(2-)was significantly inhibited,hence preventing the absorption of CO_(2).Large part of Ca(OH)_(2)became CaCO_(3)with a finer particle size,which covered the unreacted Ca(OH)_(2)surface after the reaction.Kinetic analysis showed that the CO_(2)absorption in urea-NaClO_(2)-Ca(OH)_(2)absorbent was controlled by chemical reaction in early stage,then by ash layer diffusion in later stage.展开更多
Vacuum ultraviolet(VUV) photolysis is a facile method for volatile organic compounds(VOCs) elimination, but is greatly limited by the relatively low removal efficiency and the possible secondary pollution. To overcome...Vacuum ultraviolet(VUV) photolysis is a facile method for volatile organic compounds(VOCs) elimination, but is greatly limited by the relatively low removal efficiency and the possible secondary pollution. To overcome above drawbacks, we developed an efficient method for VOCs elimination via VUV photolysis coupled with wet scrubbing process. In this coupled process, volatile toluene, a representative of VOCs, was oxidized by the gas-phase VUV photolysis, and then scrubbed into water for further oxidation by the liquid-phase VUV photolysis. More than 96% of toluene was efficiently removed by this coupled process, which was 2 times higher than that in the gas-phase VUV photolysis. This improvement was attributed to the synergistic effect between gas-phase and liquid-phase VUV photolysis. O3and HO·are the predomination reactive species for the toluene degradation in this coupled process, and the generation of O3in gas-phase VUV photolysis can efficiently enhance the HO·production in liquid-phase VUV photolysis. The result from in-situ proton transfer reaction ionization with mass analyzer(PTR-MS) further suggested that most intermediates were trapped by the wet scrubbing process and efficiently oxidized by the liquid-phase VUV photolysis, showing a high performance for controlling the secondary pollution. Furthermore, the result of stability test and the reuse of solution demonstrated that this coupled process has a highly stable and sustainable performance for toluene degradation. This study presents an environmentally benign and highly efficient VUV photolysis for gaseous VOCs removal in the wet scrubbing process.展开更多
Wet purification technology for nonferrous metal smelting flue gas is important for mercury removal;however, this technology produces a large amounts of spent scrubbing solution that contain mercury. The mercury in th...Wet purification technology for nonferrous metal smelting flue gas is important for mercury removal;however, this technology produces a large amounts of spent scrubbing solution that contain mercury. The mercury in these scrubbing solutions pose a great threat to the environment. Therefore, this research provides a novel strategy for removing and recycling mercury from the scrubbing solution, which is significant for decreasing mercury pollution while also allowing for the safe disposal of wastewater and a stable supply of mercury resources. Some critical parameters for the electrochemical reduction of mercury were studied in detail. Additionally, the electrodeposition dynamics and electroreduction mechanism for mercury were evaluated. Results suggested that over 92.4% of mercury could be removed from the scrubbing solution in the form of a Hg-Cu alloy under optimal conditions within 150 min and with a current efficiency of approximately 75%. Additionally, mercury electrodeposition was a quasi-reversible process, and the controlled step was the mass transport of the reactant. A pre-conversion step from Hg(Tu)_(4)^(2+) to Hg(Tu)_(3)^(2+) before mercury electroreduction was necessary. Then, the formed Hg(Tu)_(3)^(2+) on the cathode surface gained electrons step by step. After electrodeposition, the mercury in the spent cathode could be recycled by thermal desorption. The results of the electrochemical reduction of mercury and subsequent recycling provides a practical and easy-to-adopt alternative for recycling mercury resources and decreasing mercury contamination.展开更多
Previous research on wet scrubbers has only studied highly acidic scrubbing solutions because of their high ammonia capture efficiencies; however, the high acidity created practical problems. Lower acidity solutions w...Previous research on wet scrubbers has only studied highly acidic scrubbing solutions because of their high ammonia capture efficiencies; however, the high acidity created practical problems. Lower acidity solutions would reduce corrosion, maintenance, and cost; however, designers may need to use strategies for increasing scrubber effectiveness, such as using lower air velocities. The objective of this studywas to determine if a spray scrubber with slightly acidic and higher p H scrubbing solution (pH from 2 to 8) could effectively remove NH3 from NH3 laden air (such as animal building exhaust air), and also collect this valuable resource for rater use as a fertilizer. A bench-scale spray wet scrubber treated 20 ppmv NH3/air mixture in a countercurrent contact chamber. First, the solution pH was varied from 2 to 8while maintaining constant air velocity at 1.3 m. s-1. Next, air velocity was increased (2and 3 m.s-1) while solution pH remained constant at pH6. At 1.3 m.s -1, NH3 removal efficiencies ranged between 49.0% (pH8) and 84.3% (pH2). This study has shown that slightly acidic scrubbing solutions are a practical means of removing ammonia from air especially if the scrubber is designed to increase collisions between solution droplets and NH3 molecules. The NH3 removed from the air was held in solution as NH4+ and accumulates over time so the solution should be an excellent fertilizer.展开更多
Objective:To explore the correlation between genotypes of Orientia(O.)tsutsugamushi and clinical characteristics of scrub typhus patients.Methods:Clinical data of patients with scrub typhus admitted to different types...Objective:To explore the correlation between genotypes of Orientia(O.)tsutsugamushi and clinical characteristics of scrub typhus patients.Methods:Clinical data of patients with scrub typhus admitted to different types of medical institutions in Guangzhou from September 2012 to December 2016 were collected using medical records.Demographic data,clinical manifestations,as well as hematological and biochemical indicators of patients infected with different genotypes were analyzed and compared.Results:A total of 192 patients were included in this study,including 121 patients with Karp genotype of O.tsutsugamushi infection(63.0%),36 patients with Gilliam genotype(19.0%),23 patients with Kato genotype(12.0%),and 12 patients with TA763 genotype(6.0%)infection.The median value of albumin in patients with Karp genotype infection was significantly lower than that of Gilliam-infected patients(P=0.032).Patients with Karp genotype infection had a significantly longer hospital stay(9 days)than those with Gilliam genotype(7 days)(P=0.009)and Kato genotype infection(6 days)(P=0.005).Karp-infected patients also represented for the largest number of patients with complicated organ involvement(88/133,66.2%).Furthermore,Karp-infected patients had higher risk of developing multiple organ dysfunction syndrome(18.2%)and requiring intensive care unit treatment(15.9%).Besides,patients with Gilliam genotype(8 days)and TA763 genotype infection(7.5 days)had shorter fever duration than those with Karp genotype(9 days)and Kato genotype(9 days)infection,respectively.Conclusions:Genotypes of Orientia tsutsugamushi were associated with varying clinical manifestations,organ involvement,and treatment outcomes,suggesting that genotypes ranged in virulence.展开更多
Objective:Serological tests are widely used for scrub typhus diagnosis;however,their limitations are evident.This study aims to assess their practical value in clinical settings.Methods:We analyzed the data of adult p...Objective:Serological tests are widely used for scrub typhus diagnosis;however,their limitations are evident.This study aims to assess their practical value in clinical settings.Methods:We analyzed the data of adult patients with suspected scrub typhus who visited a tertiary care hospital in the Republic of Korea from September to December from 2019 to 2021.The included patients had an acute fever and at least one of the following ten secondary findings:myalgia,skin rash,eschar,headache,thrombocytopenia,increased liver enzyme levels,lymphadenopathy,hepatomegaly,splenomegaly,and pleural effusion.The diagnoses were grouped as scrub typhus or other diseases by two infectious disease physicians.Results:Among 136 patients who met the eligibility criteria,109 had scrub typhus and 27 had different diseases.Single and paired total antibodies using immunofluorescence assay(IFA),and total antibodies using immunochromatography-based rapid diagnostic testing(ICT)were measured in 98%,22%,and 75%of all patients,respectively.Confirmation using paired samples for scrub typhus was established at a median of 11[interquartile range(IQR)10-16]days following the first visit.Among the 82 admitted patients,the median admission time was 9(IQR 7-13)days.According to IFA,58(55%)patients with scrub typhus had total immunoglobulin titers≥1:320,while 23(85%)patients with other disease had titers<1:320.Positive ICT results were observed in 64(74%)patients with scrub typhus and 10(67%)patients with other diseases showed negative ICT results.Conclusions:Serological testing for scrub typhus is currently insufficient for decision-making in clinical practice.展开更多
Rationale:Longitudinally extensive transverse myelitis(LETM)is a rare inflammatory demyelinating disease predominantly associated with autoimmune and inflammatory disorders.Scrub typhus can cause a variety of neurolog...Rationale:Longitudinally extensive transverse myelitis(LETM)is a rare inflammatory demyelinating disease predominantly associated with autoimmune and inflammatory disorders.Scrub typhus can cause a variety of neurological complications,which may result in poor recovery and long-term disability.This report reveals a rare linkage between LETM and scrub typhus.Patient concerns:A 24-year-old female presented with a history of fever for 10 days associated with progressive quadriparesis.Physical examination revealed bilateral lower limb weakness(grade 0/5)and bilateral upper limb weakness(grade 2/5)with reduced sensation below the T3 dermatome.Diagnosis:Scrub typhus presenting with longitudinally extensive transverse myelitis.Interventions:Steroid pulse therapy with antibiotics supported by early intensive rehabilitation.Outcomes:Complete recovery was achieved.Lessons:This case report highlights the importance of considering scrub typhus as a potential cause of LETM in endemic regions,particularly in patients presenting with febrile illness and neurological symptoms.展开更多
BACKGROUND Scrub typhus is a naturally occurring acute infectious disease that is primarily transmitted through the bites of chiggers or larval mites infected by Orientia tsutsugamushi(O.tsutsugamushi).Omadacycline,a ...BACKGROUND Scrub typhus is a naturally occurring acute infectious disease that is primarily transmitted through the bites of chiggers or larval mites infected by Orientia tsutsugamushi(O.tsutsugamushi).Omadacycline,a novel tetracycline,exhibits potent antibacterial efficacy against both typical bacteria and atypical pathogens.However,omadacycline application in the treatment of scrub typhus remains limited.CASE SUMMARY In the present work,we report several cases of scrub typhus,with the main clinical symptoms being fever,the formation of eschars or ulcers,local or systemic lymphadenopathy,headache,myalgia and rash.Blood samples were collected before omadacycline was administered,and O.tsutsugamushi infection was confirmed through targeted next-generation sequencing(tNGS).After two days of treatment,the patients’symptoms,including fever,were alleviated,with no adverse drug reactions.CONCLUSION tNGS is an effective method for diagnosing scrub typhus.Omadacycline can be considered an alternative option for antiinfective therapy in patients with O.tsutsugamushi infections.展开更多
Noise pollution is becoming a critical health risk for city life.In 2020,the COVID-19 pandemic forced many cities to implement several mobility restrictions.These restrictions changed human activity patterns and decre...Noise pollution is becoming a critical health risk for city life.In 2020,the COVID-19 pandemic forced many cities to implement several mobility restrictions.These restrictions changed human activity patterns and decreased the noise levels and noise pollution that often affect urban settings.As the number of infections decreased,so did the outdoor activities,influencing the population’s perception of noise.This paper aims to evaluate the changes in noise levels associated with mobility restrictions between 2020 and 2021 in Guayaquil,Ecuador.This study used crowdsourcing with the help of smartphones and mobile applications to collect geo-referenced environmental noise data.The data was used to generate noise maps in different time frames.Finally,noise level maps were created using GIS-based tools to identify the urban areas that experienced the highest noise level variation during the study period.The results show that the most significant noise increase occurred at night.Furthermore,when analyzing noise level changes in different urban areas,the western area of Guayaquil was the one that experienced the most significant noise level variation.Findings inform the perception of noise pollution and could potentially serve as a reference for decision-makers during the proposal of public policies that ensure a better quality of life for its citizens.展开更多
Objective:To study epidemiology,clinical manifestations,and laboratory parameters of scrub typhus in Hadoti region of Rajasthan,India.Methods:A cross-sectional study was conducted on 50 patients with scrub typhus betw...Objective:To study epidemiology,clinical manifestations,and laboratory parameters of scrub typhus in Hadoti region of Rajasthan,India.Methods:A cross-sectional study was conducted on 50 patients with scrub typhus between August 2022 and November 2022.Scrub typhus was diagnosed by ELISA IgM scrub typhus antibody.The data about demography,vital parameters,and lab investigations were collected and analyzed.Results:Ninety-two percent of the patients were from a rural background(92%),86% were farmers and the majority were females.Most patients were 40-60 years old.The major complaints were fever(100%),myalgia(100%),headache(82%),and body swelling(80%).Major complications were pneumonia(68%),multiple organ dysfunction syndrome(62%),hepatitis(44%),and acute kidney injury(42%).Triglyceride levels were>200 mg/dL in 80% of patients,albumin<3.5 g/dL in 98% and eschar mark was present in 24%of patients.Conclusions:Scrub typhus is a serious acute febrile illness that can lead to multi-organ dysfunction and is associated with significant mortality.Increasing awareness regarding disease in endemic regions,early screening of patients,and treatment as early as possible could help prevent the patient from severe life-threatening complications.展开更多
Rationale:Fever with myositis and rhabdomyolysis is a medical emergency requiring prompt diagnosis and management.Scrub typhus associated myositis with rhabdomyolysis is rare.Patient concerns:A 36-year-old female pres...Rationale:Fever with myositis and rhabdomyolysis is a medical emergency requiring prompt diagnosis and management.Scrub typhus associated myositis with rhabdomyolysis is rare.Patient concerns:A 36-year-old female presented with intermittent fever up to 38.6℃,jaundice and progressive weakness of all four limbs.Diagnosis:Scrub typhus associated myositis and rhabdomyolysis.Intervention:Doxycycline 100 mg twice daily and injection of ceftriaxone 1 gm twice daily along with continuous intravenous fluids.Outcome:Fever resolved with normalization of liver function and recovery of muscle power.Lessons:Presence of myositis and rhabdomyolysis is uncommon in scrub typhus;high clinical suspicion should be kept in patients with atypical manifestations of scrub typhus.展开更多
Scrub typhus is an acute febrile vector-borne zoonotic disease caused by the obligate intracellular growth bacterium Orientia tsutsugamushi(Ot).Mites are the primary vectors and rodents play a pivotal role in the tran...Scrub typhus is an acute febrile vector-borne zoonotic disease caused by the obligate intracellular growth bacterium Orientia tsutsugamushi(Ot).Mites are the primary vectors and rodents play a pivotal role in the transmission of scrub typhus.Due to the climate warming,increased human activity and other factors,cases of scrub typhus have been increased sharply during the past decade in China,especially in the northern China.To understand the incidence trend,epidemic pattern,clinical sign,diagnosis and therapy of this diseases as well as genotype evolution of Orientia tsutsugamushi,we summarized and analyzed the current knowledge of scrub typhus in China from 2010 to 2020.The data indicated that the dominate genotypes of scrub typhus in China were Karp,Kato and Gilliam.Although the disease was distributed national wide,Yunnan,Guangzhou and Fujian showed the highest incidence rate.The main vector of scrub typhus in southwest,middle east and southeast of China appeared a geographic preference respectively.Seasonal timing,age and occupation were the key factors that relate to the peak incidence of scrub typhus.Notably,farmer was the occupation with the highest risk of Ot infection.Further study on the epidemic characteristics,risk factors,diagnosis and treatments of scrub typhus will be of benefit to a comprehensive guideline for prevention and control of this ancient disease.展开更多
Biogas upgrading for removing CO2 and other trace components from raw biogas is a necessary step before the biogas to be used as a vehicle fuel or supplied to the natural gas grid. In this work, three technologies for...Biogas upgrading for removing CO2 and other trace components from raw biogas is a necessary step before the biogas to be used as a vehicle fuel or supplied to the natural gas grid. In this work, three technologies for biogas upgrading, i.e., pressured water scrubbing(PWS), monoethanolamine aqueous scrubbing(MAS) and ionic liquid scrubbing(ILS), are studied and assessed in terms of their energy consumption and environmental impacts with the process simulation and green degree method. A non-random-two-liquid and Henry's law property method for a CO2 separation system with ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide([bmim][Tf2N]) is established and verified with experimental data. The assessment results indicate that the specific energy consumption of ILS and PWS is almost the same and much less than that of MAS. High purity CO2 product can be obtained by MAS and ILS methods, whereas no pure CO2 is recovered with the PWS. For the environmental aspect, ILS has the highest green degree production value, while MAS and PWS produce serious environmental impacts.展开更多
Solvent extraction experiments were conducted from acidic solutions containing germanium(IV) and other metal ions, such as Ga3+, Fe3+, Zn2+ and Fe2+ in hydrometallurgical process of zinc. The purpose of this wor...Solvent extraction experiments were conducted from acidic solutions containing germanium(IV) and other metal ions, such as Ga3+, Fe3+, Zn2+ and Fe2+ in hydrometallurgical process of zinc. The purpose of this work was to enhance the efficiency of the extraction and stripping processes and the selectivity of germanium and other metals, while making the method as simple as possible. Germanium was recovered from sulfuric acid, using di-(2-ethylhexyl) phosphoric acid (P2O4) as an extractant, tributyl phosphate (TBP) as modifier diluted in sulfonate kerosene and stripped by NaOH aqueous solution. Extraction studies were carried out under different acid concentrations and solvent concentrations, and optimized conditions were determined. The numbers of stages required for extraction and stripping of metal ions were determined from the McCabe-Thiele plot. The results show that the extracting and stripping efficiencies are 94.3% and 100%, respectively, through two-stage extraction and two-stage strip. Moreover, the synergistic effect of TBP on the system P2O4/kerosense/Ge4+ is revealed with respect to the extraction of germanium.展开更多
Significant attention has been given to biogas production, purification and upgrading as a renewable and clean fuel supplement. Biogas is a product of an anaerobic digestion process comprising methane, carbon dioxide,...Significant attention has been given to biogas production, purification and upgrading as a renewable and clean fuel supplement. Biogas is a product of an anaerobic digestion process comprising methane, carbon dioxide,and trace amounts of other gases. Biogas purification removes trace gases in biogas for safe utilisation. Biogas upgrading produces methane-rich biogas by removing bulk carbon dioxide from the gas mixture. Several carbon dioxide removal techniques can be applied for biogas upgrading. However, chemical absorption of carbon dioxide for biogas upgrading is of special significance due to its operation at ambient or near ambient temperature and pressure, thus reducing energy consumption. This paper reviews the chemical absorption of carbon dioxide using amine scrubbing, caustic solvent scrubbing, and amino acid salt solution scrubbing. Each of these techniques for biogas upgrading is discussed. The paper concludes that an optimised implementation of the chemical absorption techniques for biogas upgrading requires further research.展开更多
The silica sand deposit located at km 55 Jalan Pantai Kuala Terengganu-Kuala Besut in the District of Setiu, North Terengganu consists of loose sand of fine to coarse grain size which is developed over the raised beac...The silica sand deposit located at km 55 Jalan Pantai Kuala Terengganu-Kuala Besut in the District of Setiu, North Terengganu consists of loose sand of fine to coarse grain size which is developed over the raised beaches of marine origin. The underlying bedrock is believed to be either metasediment of Late Paleozoic age or intrusive granitic rocks. The average content of SiO2 is 99.3% while for the Fe2O3, Al2O3 and TiO2, their average content are 0.1%, 0.3% and 0.2% respectively. The screen analyses show that more than 90 percent of the silica sand is within 150 to 1,180 micron size range. The total area underlain by potential silica sand is about 1.9 million sq. metres with total measured reserve about 2.6 million tonnes. According to Malaysian Standard, MS 701:1981 and British Standard BS 2975:1988, silica sand for making crystal glass should meet the grade B specification in which the purity of silica sand is not less than 99.5% with only a small amount of iron oxide (0.015%), alumina (0.05%), chromium oxide (maximum 2 ppm) and other mineral oxides. In the production of crystal glass, a front loading furnace was used and maximum melting temperature was 1400 ℃. After melting process, physical evaluation on the crystal glass products were performed pertaining to complete accomplishment of melting such as existing of bubbles inside crystal glasses. In order to ensure that crystal glass quality meets the international standard, specification for crystal glass published by British standard BS 3828:1973 was taken as a guideline. Some of the parameters are density, surface hardness and refractive index. In general, silica sand from Gong Belibis, Setiu Terengganu is suitable as a raw material for making crystal glass product.展开更多
The present paper focuses on obtaining concentrate enriched with organic matter that could be suitable for a retorting process from black shale; this is black shale from the Safaga area on the Red Sea Coast. X-ray dif...The present paper focuses on obtaining concentrate enriched with organic matter that could be suitable for a retorting process from black shale; this is black shale from the Safaga area on the Red Sea Coast. X-ray diffraction and optical polarising microscope are used in evaluating black shale minerals. Attrition scrubbing and flotation were conducted for enrichment of organic matter in the black shale sample. Mineralogical studies revealed that black shale samples contain bituminous calcareous clay stone, quartz, apatite and pyrite. Rabah mine black shale contains 28% organic matter. The results of the different separation techniques indicate that attrition and flotation techniques successively enriched the organic matter in the black shale. The organic matter could be enriched in the black shale and obtained a concen- trate with 59% assavinz and 85% recovery.展开更多
基金Supported by National Science and Technology Supporting Plan (2008BADC4B02)
文摘Biogas is a kind of regenerable energy which is inexpensive and friendly to the environment, but the potential ofbiogas is difficult to develop fully in China, for most biogas have badly qualities and the utilization of it is monotonous. The suitable operation term about biogas upgrading by pressurized water scrubbing was researched through the orthogonal test in this study. Two sorts of scrubber packing included the random multidimensional hollow sphere packing and the structured screen packing were also used, and the effects of experiment factors included packing, water temperature, gas flow speed, water flow speed and washing pressure were studied. The results showed that better effect was got when the screen structured packing was used; all the five test factors affected the processing significantly in the arrange as before and had better and better significant effects.
基金supported by the National Key Research and Development Plan of China (Nos.2019YFC0214300 and 2020YFF0408886)the Central Public-interest Scientific Institution Basal Research Fund of China (Nos.PM-zx703-202104059,PM-zx703-202104-087,and PM-zx703-202204-159)the Project of Science and Technology Program of Guangzhou,China (No.202102020135)。
文摘The co-removal of CO_(2)while removing SO_(2)and NOxfrom industrial flue gas has great potential of carbon emission reduction but related research is lacking.In this study,a wet scrubbing process with various urea solutions for desulfurization and denitrification was explored for the possibility of CO_(2)absorption.The results showed that the urea-additive solutions were efficient for NOxand SO_(2)abatement,but delivered<10%CO_(2)absorption efficiency.The addition of Ca(OH)_(2)dramatically enhanced the CO_(2)absorption,remained the desulfurization efficiency,unfortunately restricted the denitrification efficiency.Among various operating parameters,pH of solution played a determining role during the absorption.The contradictory pH demands of CO_(2)absorption and denitrification were observed and discussed in detail.A higher pH of solution than 10 was favorable for CO_(2)absorption,while the oxidizing of NO to NO_(2),NO_(2)^(-)or NO_(3)^(-)by NaClO_(2)was inhibited in this condition.When7<pH<10,it was favorable for the conversion and absorption of NO and NOx.However,the conversion of HCO_(3)^(-)to CO_(3)^(2-)was significantly inhibited,hence preventing the absorption of CO_(2).Large part of Ca(OH)_(2)became CaCO_(3)with a finer particle size,which covered the unreacted Ca(OH)_(2)surface after the reaction.Kinetic analysis showed that the CO_(2)absorption in urea-NaClO_(2)-Ca(OH)_(2)absorbent was controlled by chemical reaction in early stage,then by ash layer diffusion in later stage.
基金supported by the National Natural Science Foundation of China (Nos. 22076224, 51908091 and 51908563)Open Fund of Guangdong Province Engineering Laboratory for Air Pollution Control (No. 2019323609-01)Key Laboratory of Water and Air Pollution Prevention and Control of Guangdong Province (No. 201901202)。
文摘Vacuum ultraviolet(VUV) photolysis is a facile method for volatile organic compounds(VOCs) elimination, but is greatly limited by the relatively low removal efficiency and the possible secondary pollution. To overcome above drawbacks, we developed an efficient method for VOCs elimination via VUV photolysis coupled with wet scrubbing process. In this coupled process, volatile toluene, a representative of VOCs, was oxidized by the gas-phase VUV photolysis, and then scrubbed into water for further oxidation by the liquid-phase VUV photolysis. More than 96% of toluene was efficiently removed by this coupled process, which was 2 times higher than that in the gas-phase VUV photolysis. This improvement was attributed to the synergistic effect between gas-phase and liquid-phase VUV photolysis. O3and HO·are the predomination reactive species for the toluene degradation in this coupled process, and the generation of O3in gas-phase VUV photolysis can efficiently enhance the HO·production in liquid-phase VUV photolysis. The result from in-situ proton transfer reaction ionization with mass analyzer(PTR-MS) further suggested that most intermediates were trapped by the wet scrubbing process and efficiently oxidized by the liquid-phase VUV photolysis, showing a high performance for controlling the secondary pollution. Furthermore, the result of stability test and the reuse of solution demonstrated that this coupled process has a highly stable and sustainable performance for toluene degradation. This study presents an environmentally benign and highly efficient VUV photolysis for gaseous VOCs removal in the wet scrubbing process.
基金supported by the Natural Science Foundation of China(No.51804139)the China Postdoctoral Science Foundation(No.2019M652275)the Program of Qingjiang Excellent Young Talents of Jiangxi University of Science and Technology(No.2019003)。
文摘Wet purification technology for nonferrous metal smelting flue gas is important for mercury removal;however, this technology produces a large amounts of spent scrubbing solution that contain mercury. The mercury in these scrubbing solutions pose a great threat to the environment. Therefore, this research provides a novel strategy for removing and recycling mercury from the scrubbing solution, which is significant for decreasing mercury pollution while also allowing for the safe disposal of wastewater and a stable supply of mercury resources. Some critical parameters for the electrochemical reduction of mercury were studied in detail. Additionally, the electrodeposition dynamics and electroreduction mechanism for mercury were evaluated. Results suggested that over 92.4% of mercury could be removed from the scrubbing solution in the form of a Hg-Cu alloy under optimal conditions within 150 min and with a current efficiency of approximately 75%. Additionally, mercury electrodeposition was a quasi-reversible process, and the controlled step was the mass transport of the reactant. A pre-conversion step from Hg(Tu)_(4)^(2+) to Hg(Tu)_(3)^(2+) before mercury electroreduction was necessary. Then, the formed Hg(Tu)_(3)^(2+) on the cathode surface gained electrons step by step. After electrodeposition, the mercury in the spent cathode could be recycled by thermal desorption. The results of the electrochemical reduction of mercury and subsequent recycling provides a practical and easy-to-adopt alternative for recycling mercury resources and decreasing mercury contamination.
文摘Previous research on wet scrubbers has only studied highly acidic scrubbing solutions because of their high ammonia capture efficiencies; however, the high acidity created practical problems. Lower acidity solutions would reduce corrosion, maintenance, and cost; however, designers may need to use strategies for increasing scrubber effectiveness, such as using lower air velocities. The objective of this studywas to determine if a spray scrubber with slightly acidic and higher p H scrubbing solution (pH from 2 to 8) could effectively remove NH3 from NH3 laden air (such as animal building exhaust air), and also collect this valuable resource for rater use as a fertilizer. A bench-scale spray wet scrubber treated 20 ppmv NH3/air mixture in a countercurrent contact chamber. First, the solution pH was varied from 2 to 8while maintaining constant air velocity at 1.3 m. s-1. Next, air velocity was increased (2and 3 m.s-1) while solution pH remained constant at pH6. At 1.3 m.s -1, NH3 removal efficiencies ranged between 49.0% (pH8) and 84.3% (pH2). This study has shown that slightly acidic scrubbing solutions are a practical means of removing ammonia from air especially if the scrubber is designed to increase collisions between solution droplets and NH3 molecules. The NH3 removed from the air was held in solution as NH4+ and accumulates over time so the solution should be an excellent fertilizer.
基金supported by the Science and Technology Plan Grant of Guangzhou(grant number 202102080035)the Guangzhou Health and Family Planning Science and Technology Project Western Medicine-general Guidance Project(20221A011067)+2 种基金the Basic Research Project of Key Laboratory of Guangzhou(grant number 202102100001)the Key Project of Medicine Discipline of Guangzhou(grant number 2021-2023-12)the Guangzhou Health Science and Technology Project(grant number 20221A011066).
文摘Objective:To explore the correlation between genotypes of Orientia(O.)tsutsugamushi and clinical characteristics of scrub typhus patients.Methods:Clinical data of patients with scrub typhus admitted to different types of medical institutions in Guangzhou from September 2012 to December 2016 were collected using medical records.Demographic data,clinical manifestations,as well as hematological and biochemical indicators of patients infected with different genotypes were analyzed and compared.Results:A total of 192 patients were included in this study,including 121 patients with Karp genotype of O.tsutsugamushi infection(63.0%),36 patients with Gilliam genotype(19.0%),23 patients with Kato genotype(12.0%),and 12 patients with TA763 genotype(6.0%)infection.The median value of albumin in patients with Karp genotype infection was significantly lower than that of Gilliam-infected patients(P=0.032).Patients with Karp genotype infection had a significantly longer hospital stay(9 days)than those with Gilliam genotype(7 days)(P=0.009)and Kato genotype infection(6 days)(P=0.005).Karp-infected patients also represented for the largest number of patients with complicated organ involvement(88/133,66.2%).Furthermore,Karp-infected patients had higher risk of developing multiple organ dysfunction syndrome(18.2%)and requiring intensive care unit treatment(15.9%).Besides,patients with Gilliam genotype(8 days)and TA763 genotype infection(7.5 days)had shorter fever duration than those with Karp genotype(9 days)and Kato genotype(9 days)infection,respectively.Conclusions:Genotypes of Orientia tsutsugamushi were associated with varying clinical manifestations,organ involvement,and treatment outcomes,suggesting that genotypes ranged in virulence.
基金the Korea Health Technology R&D Project through the Korea Health Industry Development Institute(KHIDI),funded by the Ministry of Health&Welfare,Republic of Korea(grant no.HI22C0306).
文摘Objective:Serological tests are widely used for scrub typhus diagnosis;however,their limitations are evident.This study aims to assess their practical value in clinical settings.Methods:We analyzed the data of adult patients with suspected scrub typhus who visited a tertiary care hospital in the Republic of Korea from September to December from 2019 to 2021.The included patients had an acute fever and at least one of the following ten secondary findings:myalgia,skin rash,eschar,headache,thrombocytopenia,increased liver enzyme levels,lymphadenopathy,hepatomegaly,splenomegaly,and pleural effusion.The diagnoses were grouped as scrub typhus or other diseases by two infectious disease physicians.Results:Among 136 patients who met the eligibility criteria,109 had scrub typhus and 27 had different diseases.Single and paired total antibodies using immunofluorescence assay(IFA),and total antibodies using immunochromatography-based rapid diagnostic testing(ICT)were measured in 98%,22%,and 75%of all patients,respectively.Confirmation using paired samples for scrub typhus was established at a median of 11[interquartile range(IQR)10-16]days following the first visit.Among the 82 admitted patients,the median admission time was 9(IQR 7-13)days.According to IFA,58(55%)patients with scrub typhus had total immunoglobulin titers≥1:320,while 23(85%)patients with other disease had titers<1:320.Positive ICT results were observed in 64(74%)patients with scrub typhus and 10(67%)patients with other diseases showed negative ICT results.Conclusions:Serological testing for scrub typhus is currently insufficient for decision-making in clinical practice.
文摘Rationale:Longitudinally extensive transverse myelitis(LETM)is a rare inflammatory demyelinating disease predominantly associated with autoimmune and inflammatory disorders.Scrub typhus can cause a variety of neurological complications,which may result in poor recovery and long-term disability.This report reveals a rare linkage between LETM and scrub typhus.Patient concerns:A 24-year-old female presented with a history of fever for 10 days associated with progressive quadriparesis.Physical examination revealed bilateral lower limb weakness(grade 0/5)and bilateral upper limb weakness(grade 2/5)with reduced sensation below the T3 dermatome.Diagnosis:Scrub typhus presenting with longitudinally extensive transverse myelitis.Interventions:Steroid pulse therapy with antibiotics supported by early intensive rehabilitation.Outcomes:Complete recovery was achieved.Lessons:This case report highlights the importance of considering scrub typhus as a potential cause of LETM in endemic regions,particularly in patients presenting with febrile illness and neurological symptoms.
基金Supported by National Natural Science Foundation of China,No.81800721the Postdoctoral Foundation of China,2020M671387.
文摘BACKGROUND Scrub typhus is a naturally occurring acute infectious disease that is primarily transmitted through the bites of chiggers or larval mites infected by Orientia tsutsugamushi(O.tsutsugamushi).Omadacycline,a novel tetracycline,exhibits potent antibacterial efficacy against both typical bacteria and atypical pathogens.However,omadacycline application in the treatment of scrub typhus remains limited.CASE SUMMARY In the present work,we report several cases of scrub typhus,with the main clinical symptoms being fever,the formation of eschars or ulcers,local or systemic lymphadenopathy,headache,myalgia and rash.Blood samples were collected before omadacycline was administered,and O.tsutsugamushi infection was confirmed through targeted next-generation sequencing(tNGS).After two days of treatment,the patients’symptoms,including fever,were alleviated,with no adverse drug reactions.CONCLUSION tNGS is an effective method for diagnosing scrub typhus.Omadacycline can be considered an alternative option for antiinfective therapy in patients with O.tsutsugamushi infections.
文摘Noise pollution is becoming a critical health risk for city life.In 2020,the COVID-19 pandemic forced many cities to implement several mobility restrictions.These restrictions changed human activity patterns and decreased the noise levels and noise pollution that often affect urban settings.As the number of infections decreased,so did the outdoor activities,influencing the population’s perception of noise.This paper aims to evaluate the changes in noise levels associated with mobility restrictions between 2020 and 2021 in Guayaquil,Ecuador.This study used crowdsourcing with the help of smartphones and mobile applications to collect geo-referenced environmental noise data.The data was used to generate noise maps in different time frames.Finally,noise level maps were created using GIS-based tools to identify the urban areas that experienced the highest noise level variation during the study period.The results show that the most significant noise increase occurred at night.Furthermore,when analyzing noise level changes in different urban areas,the western area of Guayaquil was the one that experienced the most significant noise level variation.Findings inform the perception of noise pollution and could potentially serve as a reference for decision-makers during the proposal of public policies that ensure a better quality of life for its citizens.
文摘Objective:To study epidemiology,clinical manifestations,and laboratory parameters of scrub typhus in Hadoti region of Rajasthan,India.Methods:A cross-sectional study was conducted on 50 patients with scrub typhus between August 2022 and November 2022.Scrub typhus was diagnosed by ELISA IgM scrub typhus antibody.The data about demography,vital parameters,and lab investigations were collected and analyzed.Results:Ninety-two percent of the patients were from a rural background(92%),86% were farmers and the majority were females.Most patients were 40-60 years old.The major complaints were fever(100%),myalgia(100%),headache(82%),and body swelling(80%).Major complications were pneumonia(68%),multiple organ dysfunction syndrome(62%),hepatitis(44%),and acute kidney injury(42%).Triglyceride levels were>200 mg/dL in 80% of patients,albumin<3.5 g/dL in 98% and eschar mark was present in 24%of patients.Conclusions:Scrub typhus is a serious acute febrile illness that can lead to multi-organ dysfunction and is associated with significant mortality.Increasing awareness regarding disease in endemic regions,early screening of patients,and treatment as early as possible could help prevent the patient from severe life-threatening complications.
文摘Rationale:Fever with myositis and rhabdomyolysis is a medical emergency requiring prompt diagnosis and management.Scrub typhus associated myositis with rhabdomyolysis is rare.Patient concerns:A 36-year-old female presented with intermittent fever up to 38.6℃,jaundice and progressive weakness of all four limbs.Diagnosis:Scrub typhus associated myositis and rhabdomyolysis.Intervention:Doxycycline 100 mg twice daily and injection of ceftriaxone 1 gm twice daily along with continuous intravenous fluids.Outcome:Fever resolved with normalization of liver function and recovery of muscle power.Lessons:Presence of myositis and rhabdomyolysis is uncommon in scrub typhus;high clinical suspicion should be kept in patients with atypical manifestations of scrub typhus.
基金High-level Talent Project of the Hainan Province (No.820RC628)National Natural Science Foundation of China (No.82060378,81860367)+1 种基金Natural Science Foundation Youth Project of Hainan Province (No.820QN267)Cultivation Fund of Hainan Medical College (No.HYPY201919)。
文摘Scrub typhus is an acute febrile vector-borne zoonotic disease caused by the obligate intracellular growth bacterium Orientia tsutsugamushi(Ot).Mites are the primary vectors and rodents play a pivotal role in the transmission of scrub typhus.Due to the climate warming,increased human activity and other factors,cases of scrub typhus have been increased sharply during the past decade in China,especially in the northern China.To understand the incidence trend,epidemic pattern,clinical sign,diagnosis and therapy of this diseases as well as genotype evolution of Orientia tsutsugamushi,we summarized and analyzed the current knowledge of scrub typhus in China from 2010 to 2020.The data indicated that the dominate genotypes of scrub typhus in China were Karp,Kato and Gilliam.Although the disease was distributed national wide,Yunnan,Guangzhou and Fujian showed the highest incidence rate.The main vector of scrub typhus in southwest,middle east and southeast of China appeared a geographic preference respectively.Seasonal timing,age and occupation were the key factors that relate to the peak incidence of scrub typhus.Notably,farmer was the occupation with the highest risk of Ot infection.Further study on the epidemic characteristics,risk factors,diagnosis and treatments of scrub typhus will be of benefit to a comprehensive guideline for prevention and control of this ancient disease.
基金Supported by the National Basic Research Program of China(2013CB733506,2014CB744306)the National Natural Science Foundation of China(21036007,51274183)
文摘Biogas upgrading for removing CO2 and other trace components from raw biogas is a necessary step before the biogas to be used as a vehicle fuel or supplied to the natural gas grid. In this work, three technologies for biogas upgrading, i.e., pressured water scrubbing(PWS), monoethanolamine aqueous scrubbing(MAS) and ionic liquid scrubbing(ILS), are studied and assessed in terms of their energy consumption and environmental impacts with the process simulation and green degree method. A non-random-two-liquid and Henry's law property method for a CO2 separation system with ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide([bmim][Tf2N]) is established and verified with experimental data. The assessment results indicate that the specific energy consumption of ILS and PWS is almost the same and much less than that of MAS. High purity CO2 product can be obtained by MAS and ILS methods, whereas no pure CO2 is recovered with the PWS. For the environmental aspect, ILS has the highest green degree production value, while MAS and PWS produce serious environmental impacts.
基金Project(50774094)supported by the National Natural Science Foundation of China
文摘Solvent extraction experiments were conducted from acidic solutions containing germanium(IV) and other metal ions, such as Ga3+, Fe3+, Zn2+ and Fe2+ in hydrometallurgical process of zinc. The purpose of this work was to enhance the efficiency of the extraction and stripping processes and the selectivity of germanium and other metals, while making the method as simple as possible. Germanium was recovered from sulfuric acid, using di-(2-ethylhexyl) phosphoric acid (P2O4) as an extractant, tributyl phosphate (TBP) as modifier diluted in sulfonate kerosene and stripped by NaOH aqueous solution. Extraction studies were carried out under different acid concentrations and solvent concentrations, and optimized conditions were determined. The numbers of stages required for extraction and stripping of metal ions were determined from the McCabe-Thiele plot. The results show that the extracting and stripping efficiencies are 94.3% and 100%, respectively, through two-stage extraction and two-stage strip. Moreover, the synergistic effect of TBP on the system P2O4/kerosense/Ge4+ is revealed with respect to the extraction of germanium.
文摘Significant attention has been given to biogas production, purification and upgrading as a renewable and clean fuel supplement. Biogas is a product of an anaerobic digestion process comprising methane, carbon dioxide,and trace amounts of other gases. Biogas purification removes trace gases in biogas for safe utilisation. Biogas upgrading produces methane-rich biogas by removing bulk carbon dioxide from the gas mixture. Several carbon dioxide removal techniques can be applied for biogas upgrading. However, chemical absorption of carbon dioxide for biogas upgrading is of special significance due to its operation at ambient or near ambient temperature and pressure, thus reducing energy consumption. This paper reviews the chemical absorption of carbon dioxide using amine scrubbing, caustic solvent scrubbing, and amino acid salt solution scrubbing. Each of these techniques for biogas upgrading is discussed. The paper concludes that an optimised implementation of the chemical absorption techniques for biogas upgrading requires further research.
文摘The silica sand deposit located at km 55 Jalan Pantai Kuala Terengganu-Kuala Besut in the District of Setiu, North Terengganu consists of loose sand of fine to coarse grain size which is developed over the raised beaches of marine origin. The underlying bedrock is believed to be either metasediment of Late Paleozoic age or intrusive granitic rocks. The average content of SiO2 is 99.3% while for the Fe2O3, Al2O3 and TiO2, their average content are 0.1%, 0.3% and 0.2% respectively. The screen analyses show that more than 90 percent of the silica sand is within 150 to 1,180 micron size range. The total area underlain by potential silica sand is about 1.9 million sq. metres with total measured reserve about 2.6 million tonnes. According to Malaysian Standard, MS 701:1981 and British Standard BS 2975:1988, silica sand for making crystal glass should meet the grade B specification in which the purity of silica sand is not less than 99.5% with only a small amount of iron oxide (0.015%), alumina (0.05%), chromium oxide (maximum 2 ppm) and other mineral oxides. In the production of crystal glass, a front loading furnace was used and maximum melting temperature was 1400 ℃. After melting process, physical evaluation on the crystal glass products were performed pertaining to complete accomplishment of melting such as existing of bubbles inside crystal glasses. In order to ensure that crystal glass quality meets the international standard, specification for crystal glass published by British standard BS 3828:1973 was taken as a guideline. Some of the parameters are density, surface hardness and refractive index. In general, silica sand from Gong Belibis, Setiu Terengganu is suitable as a raw material for making crystal glass product.
文摘The present paper focuses on obtaining concentrate enriched with organic matter that could be suitable for a retorting process from black shale; this is black shale from the Safaga area on the Red Sea Coast. X-ray diffraction and optical polarising microscope are used in evaluating black shale minerals. Attrition scrubbing and flotation were conducted for enrichment of organic matter in the black shale sample. Mineralogical studies revealed that black shale samples contain bituminous calcareous clay stone, quartz, apatite and pyrite. Rabah mine black shale contains 28% organic matter. The results of the different separation techniques indicate that attrition and flotation techniques successively enriched the organic matter in the black shale. The organic matter could be enriched in the black shale and obtained a concen- trate with 59% assavinz and 85% recovery.