Chitosan derived from crab shells, was used to prepare the graft polymer in aqueous solution with acrylamide （AM） and methacrylatoethyl trimethyl ammonium chloride （DMC） as raw materials and ceric ammonium nitrate...Chitosan derived from crab shells, was used to prepare the graft polymer in aqueous solution with acrylamide （AM） and methacrylatoethyl trimethyl ammonium chloride （DMC） as raw materials and ceric ammonium nitrate （CAN） as initiator. The flocculation ability of the resulting polymer （PCAD） was studied in waste water treatment experiments. Its properties were determined on the basis of the transmittance of waste water after flocculation. The effects of ehitosan and DMC content on PCAD＇s flocculation ability were studied. Floeculation experiments were also undertaken under various pH conditions. According to the experimental data, the flocculation ability could be improved when chitosan content decreased in the raw material, but the monomer conversion would decrease obviously. When the ehitosan＇s content was more than 65%, AM and DMC groups were less on each chitosan molecule. So PCAD＇s flocculation ability was poor. Similarly, high content of DMC would result in low monomer conversion and high flocculation ability. PCAD molecules with more DMC group had more positive charges. It was favorable to flocculation. However, monomer conversion would decrease with the increase of DMC content. The suitable conditions were that chitosan and DMC contents were 65% and 15-20%, respectively. The experiment data showed that PCAD had good flocculation ability under weak acidic condition. Its ability would be weakened by strong acidic or alkaline condition. The flocculation efficiency was the best at pH of 5.5 when PCAD＇s dosage was 8mg-Lk Compared with cationic polymer （the copolymer of AM and DMC, PAD）, PCAD showed better flocculation ability under acid and neutral conditions, but worse ability under alkaline condition.展开更多
The degradation of partially hydrolyzed polyacrylamide(HPAM) found in alkaline/surfactant/polymer flooding sewage was investigated using Fenton-type reagents. Different Fenton reagent treatments for HPAM degradation w...The degradation of partially hydrolyzed polyacrylamide(HPAM) found in alkaline/surfactant/polymer flooding sewage was investigated using Fenton-type reagents. Different Fenton reagent treatments for HPAM degradation were compared. The effects of pH, hydrogen peroxide(H_(2)O_(2)), ferrous ion(Fe^(2+)), and tartaric ion(C_(4)H_(4)O_(6)^(2-)) concentrations were studied. The degradation reaction occurred within a wide range of pH(3–9). The HPAM degradation performance of photo-Fenton processes using solar light and UV were compared with that of the Fenton process. The degradation rate was found to be strongly dependent on the H_(2)O_(2)/Fe^(2+)/C_(4)H_(4)O_(6)^(2-)molar ratio. The HPAM degradation efficiency was 90%, and the chemical oxygen demand removal efficiency was 85%. HPAM could be degraded into a compound with a lower molecular weight, but it was difficult to achieve complete mineralization to CO_(2). The presence of intermediate products hindered further oxidation in the Fenton process.展开更多
Once a popular injectable filler,polyacrylamide hydrogel(PAAG)has been banned in China since 2006 due to its unclear safety and long-term complications.However,it is still being used worldwide because of its huge comm...Once a popular injectable filler,polyacrylamide hydrogel(PAAG)has been banned in China since 2006 due to its unclear safety and long-term complications.However,it is still being used worldwide because of its huge commercial profit,leading to emerging complications and an urgent need for standardized clinical management.This review aimed to assess the properties,safety,and complications of PAAG and treatment strategies for its removal.展开更多
The polyacrylamide which is directly added into concrete shows strong water absorption property.Thus the construction of underwater constructure would demand high amount of water,resulting in poor workability of concr...The polyacrylamide which is directly added into concrete shows strong water absorption property.Thus the construction of underwater constructure would demand high amount of water,resulting in poor workability of concrete and strength shrinkage after hardening.Herein,a kind of anionic polyacrylamide(APAM)grafted with water reducing functional group(-COOH)was synthesized at low temperatures by partial factor design and response surface design.The structure and morphology of APAM were characterized by UV,FTIR and SEM methods.The experimental results show that the molecular weight of the synthesized APAM could reach 11 million,under the condition that the temperature was 35℃,the pH value was 8,the monomer concentration was 27wt%,the initiator dosage was 0.6wt%,and the monomer ratio(n(AM):n(AA))was 3.When the APAM was applied into the underwater slurry,it presented good flocculation and low water demand.When the dosage was 1%of the mass of the cement,the water demand increased by 12%,which could meet the self-leveling and anti-dispersity of the underwater slurry at the same time.This technology provides technical guidance for the large-scale industrial production of polyacrylamide for underwater concrete construction while achieving environmental protection during production.展开更多
High purity ammonium metavanadate(NH_(4)VO_(3))is the most vital chemical to produce V2O5,VO2,VN alloy,VFe alloy and VOSO4,which have some prospective applications for high strength steel,smart window,infrared detecto...High purity ammonium metavanadate(NH_(4)VO_(3))is the most vital chemical to produce V2O5,VO2,VN alloy,VFe alloy and VOSO4,which have some prospective applications for high strength steel,smart window,infrared detector and imaging,large scale energy storage system.NH_(4)VO_(3)is usually produced by spontaneous crystallization from the aqueous solution due to its sharp dependence of solubility on the temperature.However,hazardous chemicals in industrial effluent,include phosphorate,silicate and arsenate,causing severe damage to the environment.In this work,these impurities are selectively precipitated onto inorganic flocculants,while the vanadate dissolved in an aqueous solution keeps almost undisturbed.Therefore,high purity NH_(4)VO_(3)is produced by the crystallization from the purified solution.By screening various flocculants and precipitating parameters,polyaluminum sulfate with an optimal amount of 50 g/L,is demonstrated to selectively remove phosphorate,silicate and arsenate,corresponding to the removing efficiency of 93.39%,97.11%and 88.31%,respectively.NH_(4)VO_(3)from the purified solution holds a purity of 99.21%,in comparison with 98.33%in the product from the crude solution.This purifying technology cannot only produce NH_(4)VO_(3)with high added value,but also reduce the environmental pollution of waste liquid.展开更多
基金supported by Young Scientist Foundation (2008BS09001) from the Department of Science and Technology of Shandong Province
文摘Chitosan derived from crab shells, was used to prepare the graft polymer in aqueous solution with acrylamide （AM） and methacrylatoethyl trimethyl ammonium chloride （DMC） as raw materials and ceric ammonium nitrate （CAN） as initiator. The flocculation ability of the resulting polymer （PCAD） was studied in waste water treatment experiments. Its properties were determined on the basis of the transmittance of waste water after flocculation. The effects of ehitosan and DMC content on PCAD＇s flocculation ability were studied. Floeculation experiments were also undertaken under various pH conditions. According to the experimental data, the flocculation ability could be improved when chitosan content decreased in the raw material, but the monomer conversion would decrease obviously. When the ehitosan＇s content was more than 65%, AM and DMC groups were less on each chitosan molecule. So PCAD＇s flocculation ability was poor. Similarly, high content of DMC would result in low monomer conversion and high flocculation ability. PCAD molecules with more DMC group had more positive charges. It was favorable to flocculation. However, monomer conversion would decrease with the increase of DMC content. The suitable conditions were that chitosan and DMC contents were 65% and 15-20%, respectively. The experiment data showed that PCAD had good flocculation ability under weak acidic condition. Its ability would be weakened by strong acidic or alkaline condition. The flocculation efficiency was the best at pH of 5.5 when PCAD＇s dosage was 8mg-Lk Compared with cationic polymer （the copolymer of AM and DMC, PAD）, PCAD showed better flocculation ability under acid and neutral conditions, but worse ability under alkaline condition.
基金the Northeast Petroleum University Youth Science Foundation (No. 2019QNL-35)Guiding Science and Technology Plan Project of Daqing (No. zd-2021-39)。
文摘The degradation of partially hydrolyzed polyacrylamide(HPAM) found in alkaline/surfactant/polymer flooding sewage was investigated using Fenton-type reagents. Different Fenton reagent treatments for HPAM degradation were compared. The effects of pH, hydrogen peroxide(H_(2)O_(2)), ferrous ion(Fe^(2+)), and tartaric ion(C_(4)H_(4)O_(6)^(2-)) concentrations were studied. The degradation reaction occurred within a wide range of pH(3–9). The HPAM degradation performance of photo-Fenton processes using solar light and UV were compared with that of the Fenton process. The degradation rate was found to be strongly dependent on the H_(2)O_(2)/Fe^(2+)/C_(4)H_(4)O_(6)^(2-)molar ratio. The HPAM degradation efficiency was 90%, and the chemical oxygen demand removal efficiency was 85%. HPAM could be degraded into a compound with a lower molecular weight, but it was difficult to achieve complete mineralization to CO_(2). The presence of intermediate products hindered further oxidation in the Fenton process.
文摘Once a popular injectable filler,polyacrylamide hydrogel(PAAG)has been banned in China since 2006 due to its unclear safety and long-term complications.However,it is still being used worldwide because of its huge commercial profit,leading to emerging complications and an urgent need for standardized clinical management.This review aimed to assess the properties,safety,and complications of PAAG and treatment strategies for its removal.
基金Funded by the National Natural Science Foundation of China(No.51778378)the Natural Science Foundation of Hebei Province(No.E2022210103)。
文摘The polyacrylamide which is directly added into concrete shows strong water absorption property.Thus the construction of underwater constructure would demand high amount of water,resulting in poor workability of concrete and strength shrinkage after hardening.Herein,a kind of anionic polyacrylamide(APAM)grafted with water reducing functional group(-COOH)was synthesized at low temperatures by partial factor design and response surface design.The structure and morphology of APAM were characterized by UV,FTIR and SEM methods.The experimental results show that the molecular weight of the synthesized APAM could reach 11 million,under the condition that the temperature was 35℃,the pH value was 8,the monomer concentration was 27wt%,the initiator dosage was 0.6wt%,and the monomer ratio(n(AM):n(AA))was 3.When the APAM was applied into the underwater slurry,it presented good flocculation and low water demand.When the dosage was 1%of the mass of the cement,the water demand increased by 12%,which could meet the self-leveling and anti-dispersity of the underwater slurry at the same time.This technology provides technical guidance for the large-scale industrial production of polyacrylamide for underwater concrete construction while achieving environmental protection during production.
基金support from the Natural Science Foundation of Hubei Province(2020BED011)XPS characterizations and ICP-OES were carried out in the Analytical and Testing Center in HUST.
文摘High purity ammonium metavanadate(NH_(4)VO_(3))is the most vital chemical to produce V2O5,VO2,VN alloy,VFe alloy and VOSO4,which have some prospective applications for high strength steel,smart window,infrared detector and imaging,large scale energy storage system.NH_(4)VO_(3)is usually produced by spontaneous crystallization from the aqueous solution due to its sharp dependence of solubility on the temperature.However,hazardous chemicals in industrial effluent,include phosphorate,silicate and arsenate,causing severe damage to the environment.In this work,these impurities are selectively precipitated onto inorganic flocculants,while the vanadate dissolved in an aqueous solution keeps almost undisturbed.Therefore,high purity NH_(4)VO_(3)is produced by the crystallization from the purified solution.By screening various flocculants and precipitating parameters,polyaluminum sulfate with an optimal amount of 50 g/L,is demonstrated to selectively remove phosphorate,silicate and arsenate,corresponding to the removing efficiency of 93.39%,97.11%and 88.31%,respectively.NH_(4)VO_(3)from the purified solution holds a purity of 99.21%,in comparison with 98.33%in the product from the crude solution.This purifying technology cannot only produce NH_(4)VO_(3)with high added value,but also reduce the environmental pollution of waste liquid.
