A green cross-linking method for the preparation of renewable threedimensional graphene sponges for efficient adsorption of Congo red dye

Graphene-based materials possess significant potential for the treatment of dye wastewater due to their exceptional adsorption properties toward stubborn pollutants.However,their utilization is hindered by high preparation costs,low yields,environmental pollution during synthesis,and challenges in regenerating the adsorbent.This study proposes a novel approach to address these limitations by developing nitrogen-doped three-dimensional(3D)polyvinyl alcohol(PVA)crosslinked graphene sponges(N-PGA)using a cross-linking method with ammonium carbonate.This method offers a relatively mild,environmentally friendly approach.Ammonium carbonate serves as both a reducing and modifying agent,facilitating the formation of the intrinsic structure of N-PGA and acting as a nitrogen source.Meanwhile,PVA is utilized as the cross-linking agent.The results demonstrate that N-PGA exhibits a favorable internal 3D hierarchical porous structure and possesses robust mechanical properties.The measured specific surface area(BET)of N-PGA was as high as406.538 m^(2)·g^(-1),which was favorable for its efficient adsorption of Congo red(CR)dye molecules.At an initial concentration of 50 mg·L^(-1),N-PGA achieved an impressive removal rate of 89.6%and an adsorption capacity of 112 mg·g^(-1)for CR dye.Furthermore,it retained 79%of its initial adsorption capacity after 10 cycles,demonstrating excellent regeneration performance.In summary,the synthesized N-PGA displays remarkable efficacy in the adsorption of CR dye in wastewater,opening up new possibilities for utilizing 3D porous graphene nanomaterials as efficient adsorbents in wastewater treatment.

Palaeogene Sandstones of the Manika Plateau in Kolwezi (DR Congo): Sedimentological and Geochemical Characterization, Provenance, Palaeoalteration and Tectonic Context

This work presents a study of the Paleogene sandstones of the Manika plateau in Kolwezi, DR Congo. These sandstones belong to the “Grès polymorphes” group, which together with the overlying “Sables ocre” makes up the Kalahari Supergroup. Sedimentological and geochemical analyses have enabled us to characterize these sandstones and determine their origin, the conditions of their formation and the tectonic context in which they were developed. The results show that the sandstones are quartz arenites with a high level of mineralogical, textural and chemical maturity. They are recycled sandstones, formed in an intracratonic sedimentary basin, in the context of a passive continental margin, after a long fluvial transport of sediments. These sandstones initially come from intense alteration of magmatic rocks with felsic composition, mainly tonalite-trondhjemite-granodiorite (TTG) complexes, in hot, humid palaeoclimatic conditions and oxidizing environments.

Fatty Acid Composition of Hazelnut Kernel Oil from Coula edulis Collected in the Republic of Congo

Coula edulis is non-timber forest product (NTFP) used in Africa for its hazelnuts, which contain edible seeds with a demonstrated nutritional potential. However, there have been very few scientific studies of this species in the Republic of Congo. Thus, the aim of the current study was therefore to determine the fatty acid composition of the oil extracted from Coula edulis hazelnut seeds collected at random in the Republic of Congo. The oil was extracted using the Soxhlet method and its fatty acid composition was determined by gas chromatography. The extracted oil from Coula edulis hazelnut kernels is rich in monounsaturated fatty acids (95.28%), particularly oleic acid (94.5%), which classifies it as an oleic oil and gives it interesting nutritional and therapeutic properties. On the other hand, saturated fatty acids (4.15%) and polyunsaturated fatty acids (0.35%) are not well represented. Its low poly-unsaturated fatty acid content makes it more stable when stored at room temperature.

Congophilic fibrils in the glomeruli with polyclonal immunoglobulin gamma staining-another cause for diagnostic overlap:A case report

BACKGROUND Glomerulopathy with fibrillary deposits is not uncommon in routine nephropathology practice,with amyloidosis and fibrillary glomerulonephritis being the two most frequently encountered entities.Renal amyloid heavy and light chain(AHL)is relatively uncommon and its biopsy diagnosis is usually limited to cases that show strong equivalent staining for a single immunoglobulin(Ig)heavy chain and a single light chain,further supported by mass spectrometry(MS)and serum studies for monoclonal protein.But polyclonal light chain staining can pose a challenge.CASE SUMMARY Herein we present a challenging case of renal AHL with polyclonal and polytypic Ig gamma(IgG)staining pattern by immunofluorescence.The patient is a 62-yearold Caucasian male who presented to an outside institution with a serum creatinine of up to 8.1 mg/dL and nephrotic range proteinuria.Despite the finding of a polyclonal and polytypic staining pattern on immunofluorescence,ultrastructural study of the renal biopsy demonstrated the presence of fibrils with a mean diameter of 10 nm.Congo red was positive while DNAJB9 was negative.MS suggested a diagnosis of amyloid AHL type with IgG and lambda,but kappa light chains were also present supporting the immunofluorescence staining results.Serum immunofixation studies demonstrated IgG lambda monoclonal spike.The patient was started on chemotherapy.The chronic renal injury however was quite advanced and he ended up needing dialysis shortly after.CONCLUSION Tissue diagnosis of AHL amyloid can be tricky.Thorough confirmation using other available diagnostic techniques is recommended in such cases.

Epidemiological and Paraclinical Aspects of Helicobacter pylori Infection among Hepatitis B Virus Carriers in the Republic of Congo

Objective: Describe the epidemiological and paraclinical aspects of HP infection in hepatitis B virus carriers. Population and Method: This was a descriptive cross-sectional study running from January 1 to August 30, 2019, a period of 8 months. It took place in the Hospital Centers of the two major cities of Congo (Brazzaville and Pointe-Noire). The target population of our study consists of patients carrying HBV under antiviral treatment or not. Patients aged at least 18 years and consenting with a biological and morphological assessment were included. We did not include in our study patients taking or having taken antibiotics and/or PPIs less than 4 weeks ago. We excluded all patients who did not deposit fresh stools and those in whom stool extraction could not be done manually. The variables studied covered sociodemographic, clinical and paraclinical aspects. Data entry was done using Excel 8.0 software. Statistical analysis was carried out with SPSS 20.0 software. Results: During our study, we included 169 patients. The frequency of HPAG in the stools of HBV carriers in our study population was 63.9% (n = 109). Male patients represented 69% (n = 75) and female patients represented 31% (n = 34). The average age of the patients is 43.92 ± 13.51 years with extremes of 18 years and 80 years. Concerning profession, unemployed patients and those working in the private sector were the most represented in respectively 28.4% (n = 31) and 22.9% (n = 25) without statistical link. Households comprising between 4 - 10 people and the use of public latrines were the risk factors most represented in respectively 69% (n = 75) and 88% (n = 96) without statistical link. Clinically, hepatomegaly and signs of portal hypertension were most represented in 53% (n = 58) and 47% (n = 51). Biologically, HBV DNA was detectable in 60.5% of cases (n = 66).

Physicochemical and Bacteriological Profile of Bilanko and Ngamakala Peat Bog Soils (Republic of Congo)

Peatlands are unique and complex natural ecosystems that are part of the most important carbon reservoirs on our planet, home to a diversity of microorganisms responsible for fermentation, humification or peat. The aim is to understand chemical and biological indicators of peatland soils. This work aims to determine the physicochemical and bacteriological profile and lipolytic activity of soil bacteria in Bilanko peatlands. The bacterial profile with the production of lipases is carried out by classical microbiology techniques. The results show that the soils are moderately acidic with temperatures of 27.8˚C ± 0.01˚C for Bilanko and 27.1˚C ± 0.57˚C for Ngamakala. The electroconductivity (EC) varies from (9.52 ± 0.002) μS/cm to (39.01 ± 1.4) μS/cm with low turbidity of (2.04 ± 0.66) mg/L to (31.02 ± 0.84) mg/L and low ion concentrations with, however, a richness in phenolic compounds for Bilanko compared to Ngamakala. FMAT diversity ranged from (1.71 ± 0.88)∙104 UFC/g to (2.92 ± 0.07)∙105 UFC/g for Bilanko and (1.30 ± 0.73)∙104 UFC/g to (2.89 ± 0.06)∙104 UFC/g for Ngamakala. Bacillus loads ranged from (5.20 ± 1.40)∙103 CFU/g to (1.22 ± 0.13)∙104 CFU/g and from (1.11 ± 0.13)∙104 CFU/g to (9.20 ± 2.05)∙103 CFU/g;enterobacteria loads from (1.40 ± 0.76)∙103 CFU/g to (8.80 ± 1.73)∙103 CFU/g and from (1.01 ± 0.02)∙103 CFU/g to (9.20 ± 2.05)∙103 CFU/g;in Pseudomonas from 0 to (2.30 ± 0.53)∙102 CFU/g and from 0 to (8.90 ± 2.35)∙102 CFU/g for Bilanko and Ngamakala respectively. These results reveal a variation in bacterial similarity and distribution in the Bilanko and Ngamakala peat bogs.

Principle for the Installation of Accommodation for Sick guards in Public Health Establishments in Brazzaville in the Republic of Congo

The results of scientific studies of human social facts in the field of health show that the management of a patient should involve the patient’s entourage,whatever the status or size of the health establishment.In healthcare establishments in the Congo,the following are recognised as being responsible for medical care:specialist doctors,doctors,midwives,nurses and care assistants.The patient’s family and close friends are responsible for looking after the patient and financing care.The hospital infrastructure does not provide any space for the patient warden who accompany the patient during reception and hospitalisation.This makes Congolese hospitals inefficient for patient care.How can we integrate the function of the Sick guard and the assistance of the family,in order to reduce the mortality rate and repair the harm caused to patients requiring the presence of relatives during their stay in hospital,which is considered to be a dangerous place?This article examines the functional principles for configuring the space that patient warden would occupy in the patient care system.On the basis of a documentary analysis of sociological and architectural studies of existing facilities,this article proposes a typical accommodation model with the spaces needed to ensure the well-being and effectiveness of the patient warden with the patient.These are rooms with minimum space for 2 to 4 individual beds,equipped with toilets and showers.The accommodation has a dining area,kitchen and laundry facilities.In the future,this accommodation will become part of the hospital estate and may be occupied by orderlies and patient warden recruited by the hospital administration.

What Is the Impact of Ploughing on Eucalyptus Plantations in Bambou Mingali (Plateaux Batéké, Republic of Congo)?

Soil ploughing is an important stage in the preparation of planting, causing disturbance to the physical, chemical and biological properties of the soil. Soil ploughing can affect the availability of nutrients and water resources, and its effect can be short, medium or long-term. Soil ploughing accelerates surface heating and air circulation and encourages mineralisation by transforming organic matter into mineral salts, making nutrients soluble and accessible to plants. The aim of this study is to determine how soil ploughing affects the distribution of nutrients in the soil profile. The study focuses on nitrogen, carbon, phosphorus, calcium and magnesium, which are major elements of soil fertility on the Batéké plateaux in Congo. The results indicate that ploughing significantly modifies the distribution at depth des elements nutritifs: there is more accumulation at the surface than at depth (ei: nitrogen 1.34 t/ha ± 0.035 at 10 cm compared with 1.034 t/ha ± 0.098 at 50 cm) with a higher concentration of carbon (13.89 t/ha ± 0.87) followed by nitrogen (1.34 t/ha ± 0.035).

Investigating Non-Compliance with COVID-19 Vaccination through Hesitancy, Refusal, and Access Limitation: A Community-Based Survey from the Democratic Republic of the Congo

Introduction: Vaccination plays a pivotal role in mitigating the repercussions of the COVID-19 pandemic. However, vaccination campaigns encounter obstacles, especially in developing countries like the Democratic Republic of the Congo (DRC). This study aimed at investigating the roles of vaccine hesitancy, refusal, and access barriers, while identifying individual-level factors associated with non-vaccination in Mbujimayi, DRC. Methods: A community-based cross-sectional survey was conducted in three health districts and included 1496 residents. Attitudes and behaviors related to seeking COVID-19 vaccination were assessed using a standardized questionnaire. Hierarchical logistic regression modeling was used to assess factors potentially affecting non-compliance with vaccination. Results: Among participants (median age = 33, IQR = 23.3, M/F sex ratio = 0.7), 60% displayed misconceptions about COVID-19 or its vaccine, while only 35.2% perceived COVID-19 as a significant health threat. Vaccination coverage was estimated at 49.1% (95% CI: 47.5;52.6), with 71.8% of vaccinated individuals having received one dose. Among the unvaccinated individuals, 50.9% expressed no intention to be vaccinated in the future, citing hesitation (30.4%) or refusal (39.6%) mainly due to side effects or distrust of vaccines. Conversely, 32.7% of the unvaccinated persons expressed access barriers despite willingness to be vaccinated. Misconceptions about COVID-19 and its vaccines were the main drivers of vaccination non-compliance. Conclusion: These findings demonstrate significant vaccine non-compliance driven by hesitancy, refusal, and access barriers. Strategies to enhance vaccination coverage and pandemic preparedness should address misconceptions, sociodemographic barriers, and geographic disparities.

Feeding Habits of Bryconalestes tholloni (Pellegrin, 1901) (Characiformes: Alestidae) from Mafoubou River (Sous-Affluent of Niari River) in Congo Brazzaville

The diet of Bryconalestes tholloni from Mafoubou River, Sous-affluent of Niari River was studied by examining the stomach contents of 75 specimens captured using the cast nets. This study is the first realized on the trophic ecology of a fish species of Niari Basin. Three stations were sampled monthly from July to December 2019. The diet was analyzed according to hydrological season and fish size. The vacuity coefficient is 27%, feeding habits of Bryconalestes tholloni were analyzed using the preponderance index which combines the occurrence percentage and the weight percentage. Bryconalestes tholloni is insectivorous (Ip = 95.54%) and becomes omnivorus to predominantly frugivorous, the preponderance index of fruits is equal to 93.6% in large individuals. There is no variation in diet according to the season. These results constitute a first database on the feeding habits Niari Basin fishes.

Coordination of Regulation Devices for Damping Power Oscillations in a Dynamic Disturbance Context: A Fuzzy Logic-Based Approach Applied to the Electrical Grid of the Republic of Congo

This article presents a fuzzy logic-based approach to coordinate the control devices of the power system, such as Power System Stabilizers (PSS) and Static Synchronous Compensators (STATCOM), to damp power oscillations caused by dynamic disturbances. At first, we used the Lyapunov method to study the dynamic stability of the power grid in the Republic of Congo. This method allowed us to analyze the eigenvalues of the state variable matrix and highlight the eigenvalues in the complex plane. Secondly, we proposed a fuzzy logic-based controller to account for uncertainties existing near the thresholds. The inputs to this controller are the generator speed and generator rotor angle. We demonstrated the effectiveness and feasibility of this fuzzy control by applying it to the power grid of the Republic of Congo, with three power stabilizers and two STATCOMs. .

Abdominoplasty, Liposuction and Brazilian Butt Lift (BBL) in Kinshasa in the Democratic Republic of Congo. My Experience in This Aesthetic Plastic Surgery with Black African Women in a Low-Income Country

Background: In low-income African countries, the demand and use of plastic surgery operations including abdominoplasty, liposuction and Brazilian butt lift (BBL) are increasing. The goal of this work is to present my experience and the challenges of this aesthetic plastic surgery among black African women. Material and Methods: A retrospective study was conducted about the abdominoplasties, liposuctions and Brazilian butt lift (BBL) which I operated in public and private hospitals at Kinshasa (Democratic Republic of Congo) in black African women. It covers a period of 13 years, going from December 1, 2010 to December 1, 2023. For this study, I had at least 6 months period (to Juin 1, 2024) to assess the occurrence of early and late postoperative complications. Results: I performed 84 abdominoplasties, 144 liposuctions and 23 Brazilian butt lifts (BBL). The average age at the time of abdominoplasty was 44 years with extremes ranging from 26 to 55 years and a concentration of cases (60.7%) in the age group of 40 to 49 years. The age group of 20 to 29 years old represented the lowest rate of requests for abdominoplasty (4.7%). Patients with a BMI of 30 to 2 were the majority (61.9%), followed by those between 25 to 2 (29.7%). 67.8% of patients were obese (BMI ≥ 30 kg/m2). The average age at the time of liposuction was 41 years with extremes ranging from 21 years to 69 years;and more than half of cases (68%) in the age group between 30 and 49 years. As for Brazilian butt lift (BBL), the average age was 33 years with extremes ranging from 24 to 42 years and a concentration of patients (91.3%) between 20 and 39 years. The immediate postoperative complications of abdominoplasties observed were: seroma in 7% of cases, hematoma and partial infection of the surgical site in 5% of cases. Pathological scars (hypertrophic, keloid) after abdominoplasties were observed in 9% of cases. The most common complication of liposuction was contour deformity. I observed 16 patients (11.1%) with soft-tissue depressions or elevations, skin panniculus or folds. For Brazalian Butt Lift (BBL), complications like asymmetry for 2 patients (8.9%), contour irregularities for 2 patients (8.9%), and excessive fat removal for 6 patients (26%), had observed. I have not recorded any cases of death or pulmonary embolism. Conclusion: I perform aesthetic plastic surgery procedures in black African women with a high socioeconomic standard of living compared to the average of the general population. The renunciation of planned surgery is motivated by the impossibility of paying the cost of the operation as well as by popular and religious perceptions regarding cosmetic surgery. The results of these aesthetic plastic surgery procedures carried out are very satisfactory for them. The challenges to overcome are mainly threefold: the unforeseeable complications of these cosmetic plastic surgery procedures, popular and religious perceptions of cosmetic surgery as well as the poverty of the population.

Analysis of Maximum PowerPoint Tracking (MPPT) Adaptability in Inverters of the Three-Phase Photovoltaic Systems Integrated into the Electrical Grid of Congo-Brazzaville

This paper investigates the adaptability of Maximum Power Point Tracking (MPPT) algorithms in single-stage three-phase photovoltaic (PV) systems connected to the grid of Congo-Brazzaville and compares the attributes of various conventional, significance and novelty of controller system of the proposed of method and improved Incremental Conductance algorithms, Perturbation and Observation Techniques, and other Maximum Power Point Tracking (MPPT) algorithms in normal and partial shading conditions. Performance evaluation techniques are discussed on the basis of the dynamic parameters of the PV system although the control of this structure is relatively advanced technology but the conversion efficiency is difficult to improve due to increase in transformation series. The single stage topology has a simple topology with high reliability and efficiency because of high power consumption, but control algorithm is more complex because of its power convert main circuit a new strategy is being developed. This paper describes a method for maximum power point tracking (MPPT) in the single-stage and three single-phase PV grid-connected system. In the paper, the nonlinear output characteristics of the PV including I-V & P-V are obtained in changed solar insulations or temperature based on MATLAB, and the MPPT algorithm which is based on the P & O algorithm method, compared with Incremental Conductance, is also described, a dimensioning of the impedance adapter for better stabilization. A comparison SPWM and SVPWM control methods in the case of a grid connection applied to the electrical grid of Republic of Congo and their influences on the dynamic performance of the system and their impact in reducing the harmonic rate for better injection into the grid. The simulation model of three single-phase PV grid-connected system is built, and simulation results show the MPPT algorithm has excellent dynamic and static performances, which verifies the Incremental Conductance is effective for MPPT in the single-stage and three single-phase PV grid-connected system.

Health Safety of the Fish from the Luapula River in Democratic Republic of Congo

The Luapula River has received mining discharges from Lubumbashi and Kipushi Gecamines for several decades and from the CHEMAF company since 2005. It also received mining waste from SODIMICO. The Luapula River has Lake Banguelo as its source in Zambia and flows into Lake Moero, which is located on the border between Zambia and the Democratic Republic of Congo. The objective of this study is to assess the health safety of the fish from the Luapula River. Fish samples were collected in August 2015 at the site of the locality of Kasenga located downstream of the mining activities (n = 14) and presumed to be polluted. On the other hand, reference fish samples were taken upstream of any mining activity of the Panda, Kasungwe and Congo Rivers at the sections located near their sources and presumed not to be polluted by mining wastes. (n = 11). Ten Metal Trace Elements (MTE) were assayed at the laboratory of the Congolese Control Office (OCC) of Lubumbashi and at the laboratory of the Catholic University of Leuven in Belgium using ICP-OES and ICP-MS. To assess and evaluate the health safety of fish from the Luapula River, the concentrations of fish samples from the Luapula River were compared with the concentrations of the reference fish samples from the Panda Kasungwe and Congo rivers by the Wilcoxon test. The concentrations of fish samples from the Congo River were also compared with the maximum acceptable metal trace element concentrations established by the FAO, WHO, EU (European Union) and other regulatory bodies. as reported by Akoto et al. The results of this study showed that the fish from the Luapula River is contaminated in Cd, Cu, Ni and Pb, and are not fit for human consumption. The results obtained will be brought to attention of the decision-makers of the Province of Haut-Katanga, so that measures can be taken to ban metallurgical factories to drump their mining wastes into waterways.

Gas Valorization in the Republic of Congo: Production of Electricity from National Gas Reserves

The environmental impact of greenhouse gases based on natural gas flaring influences the rate of gas recovery around the world. In the Republic of Congo, the natural gas reserve in 2019 is estimated at 90 billion cubic meters (BCM). In this study, from the Congolese gas reserve we used five gas turbines with a capacity of 150 MW each;these five turbines consume 1.69 billion cubic meters (BCM)/year for the power of 273.750 MW and consumption of 6.57 billion kilowatt-hours. The results of this study revealed that an investment capital of 192,305,137 euros was required with a net profit of 9,581,250 euros at an annual rate of return of 4.98% with an investment payback period of approximately 20 years. This will allow the Congolese government to accomplish its policy of valuing gas and developing the country;the electricity produced by the National Petroleum Company of Congo (SNPC) will be sold to the Electrical Energy of Congo (E2C) at 0.06 euro/kWh.

Preparation and characterization of MWCNTs/LDHs nanohybrids for removal of Congo red from aqueous solution

The assembly of layered double hydroxides （LDHs） and multi-walled carbon nanotubes （MWCNTs） nanohybrids was prepared as MWCNTs/LDHs by co-precipitation. The synthesized nanoparticles were characterized by using XRD, FT-IR, SEM/EDX, TGA and BET. XRD and SEM studies proved that MWCNTs phases did not enter into the interlayers of LDHs, they dispersed over the LDHs surface homogeneously. BET results showed that MWCNTs/LDHs possessed hierarchically porous nanostructure with large surface area （124.974 m^2/g） and great pore volume （0.604 cm^3/g）. Batch experiments were conducted to study the adsorption efficiency of Congo red （CR）. It was worthy to note that MWCNTs/LDHs exhibited excellent adsorption performance with the maximum CR adsorption capacity of 595.8 mg/g in weak acidic environment. The adsorption kinetics and isotherm parameters can be well described by the pseudo-second-order and the Langmuir isotherm models, respectively. The thermodynamic studies indicated that the adsorption process was spontaneous and endothermic.

Adsorption of congo red on mesoporous activated carbon prepared by CO2 physical activation

This research demonstrates the production of mesoporous activated carbon from sargassum fusiforme via physical activation with carbon dioxide.Central composite design was applied to conduct the experiments at different levels by altering three operating parameters.Activation temperature(766-934℃),CO2 flow rate(0.8-2.8 L·min^-1)and activation time(5-55 min)were the variables examined in this study.The effect of parameters on the specific surface area,total pore volume and burn-out rate of activated carbon was studied,and the influential parameters of methylene blue adsorption value were identified employing analysis of variance.The optimum conditions for maximum methylene blue adsorption value were:activation temperature=900℃,activation time=29.05 min and CO2 flow rate=1.8 L·min(-1).The activated carbon produced under optimum conditions was characterized by BET,FTIR and SEM.The adsorption behavior on congo red was studied.The effect of parameters on the adsorbent dosage,temperature,PH and initial congo red concentration was investigated.The adsorption properties of the activated carbon were investigated by kinetics.The equilibrium removal rate and maximum adsorption capacity reaches up to 94.72%,234 mg·g^-1,respectively when initial congo red concentration is 200 mg·L^-1 under adsorbent dosage(0.8 g·L^-1),temperature(30℃),PH7.

Discoloration of Congo Red by Rod-Plate Dielectric Barrier Discharge Processes at Atmospheric Pressure

A dielectric barrier discharge （DBD） reactor with a rod-plate electrode configuration was used for the oxidative decomposition of Congo red dye in an aqueous solution. Plasma was generated in the gas space above the water interface under atmospheric pressure. Discharge characteristics were analyzed by voltage-current waveforms. Effects of applied voltage, initial conductivity, and initial concentration were also analyzed. Congo red discoloration increased with increased applied voltage and decreased conductivity. The initial conductivity significantly influenced the Congo red discoloration. Under the same conditions, the highest discoloration rate was obtained at 25 mg/L. The presence of ferrous ions in the solutions had a substantial positive effect on Fenton dye degradation and flocculation. At an applied voltage of 20 kV, about 100% of dye was degraded after 4 min of Fe^2＋/DBD treatment. Results showed that adding a certain dosage of hydrogen peroxide to the wastewater could enhance the discoloration rate. Possible pathways of Congo red discoloration by DBD plasma were proposed based on GC/MS, FTIR, and UV-vis spectroscopy analyses.

Preparation and Characterization of Mg/Al/Fe Hydrotalcite with Superb Absorption Capacity toward Congo Red

Mg/Al/Fe layered double hydroxide(MAF-LDH1) was prepared by solvothermal method with the sodium dodecyl sulfate as the template, and the ethanol system was benefit to growth of sample. The nature in the resulting MAF-LDH was investigated by X-ray diffraction, field emission scanning electron microscopy, Fourier transformed infrared spectra, thermogravimetric analysis, and N2 adsorption-desorption.The morphology of MAF-LDH1 is petal-like with the size of 400-500 nm and the thickness about 10-20 nm. The adsorption performance of the samples was evaluated by absorption of the Congo red(CR) solutions. Compared with Mg/Al layered double hydroxide(MA-LDH), the maximum adsorption capacities of the MAF-LDH1 samples were 943.4 mg/g which was greatly enhanced. Furthermore, after seven cycling tests, the adsorption performance was still up to 90%. Theoretical calculation results revealed that the adsorption process was spontaneous and followed the pseudo-second-order kinetic model and Freundlich model. This work provides a promising alternative strategy to enhance the adsorptive properties of hydrotalcite-like materials.

Radio Frequency Underwater Discharge Operation and Its Application to Congo Red Degradation

Radio frequency （RF） underwater discharge operation was performed for different liquid conductivities driven by different frequencies ranging from 13.56 MHz to 60 MHz, and its application to organic degradation was investigated. The RF underwater discharge was observed to be generated within the bubble at electrode surface formed by RF and plasma heating. It was shown that the sizes of the bubbles and plasmas increased as the driving frequency and the input power went up. The breakdown voltage decreased rapidly with the increase of the water conductivity and driving frequency. Comparative experiments of the UV-VIS absorbance spectra of Congo Red solution before and after discharge suggested effective degradation of the organic dye due to the active species generated during the discharge, such as .OH, .O, .H, etc. revealed by optical emission spectroscopy. The results show that higher exciting frequency and lower conduc- tivity of the solution are more effective for organic degradation. With the combination of Fourier Transform Infrared Spectroscopy （FT-IR） and Liquid Chromatography-Mass Spectrometry （LC- MS） data, one possible degradation process was proposed and the main conceivable components and structures of the products were also presented.