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
对4种二烯丙基甲基烷基（n=12,14,16,18）溴化铵（标记为C12,C14,C16,C18）的性质与性能进行了研究。通过测定其热稳定性、表面活性和絮凝性能,考察产物结构对其性质与性能的影响规律。结果表明,季铵盐C12~C18的主要分解温度分别为170~...对4种二烯丙基甲基烷基（n=12,14,16,18）溴化铵（标记为C12,C14,C16,C18）的性质与性能进行了研究。通过测定其热稳定性、表面活性和絮凝性能,考察产物结构对其性质与性能的影响规律。结果表明,季铵盐C12~C18的主要分解温度分别为170~300℃、172~303℃、170~293℃和170~310℃,对应失重率分别为92.8%、92.6%、96.4%和87.4%;临界胶束浓度（cmc）和临界胶束浓度下的表面张力（γcmc）分别为5.2、3.5、1.4、1.1 mmol/L和26.6、25.2、33.8、35.8 m N/m,显示出较高的表面活性;季铵盐C16的发泡与稳泡性能最好,C12的Krafft点〈0℃,C14、C16和C18的Krafft点分别为1、8和19℃;C12和C14分别对膨润土和高岭土的絮凝能力最强,表明单体的絮凝性能具有结构选择性。展开更多
Graft copolymerization is one of the most attractive methods to modify natural polymers. In this study, graft copolymerization of acylic acid onto chitosan in aqueous media by ceric ammonium nitrate was investigated. ...Graft copolymerization is one of the most attractive methods to modify natural polymers. In this study, graft copolymerization of acylic acid onto chitosan in aqueous media by ceric ammonium nitrate was investigated. The graft copolymerization reaction was carried out in a three necked flask maintained at 70＋/-0.05 ℃ under nitrogen atmosphere in a homogeneous aqueous phase （containing a small potion of acetic acid） by using ceric ammonium nitrate as an initiator. Evidence of grafting was obtained. The synthetic conditions were systematically optimized through studying the influential factors on grafting. The effectiveness of each individual factor was investigated by calculating and monitoring the variations of the grafting parameters [like monomer conversation Cm, grafting efficiency （Ge） and viscosity]. Under optimum conditions monomer conversion of 100.5% and graft efficiency of 94% were obtained, at temperature of 70℃. Flocculating ability of the copolymerization product of chitosan was studied by using Kaolin suspension as the flocculating object. And the application of the product was applied in Huayue dyeing plant. The results indicate that the higher the viscosity is, the better the flocculating ability of the copolymerization product of chitosan will be. The flocculating percentage reaches 96.0%, when the concentration of the product is only 1.0 mg/L and pH fixed at 7.0. Suitable separating mixtures for the grafted copolymer were chosen and the investigation of flocculation ability of the grafted copolymer was carried out with the aim of developing a good flocculant for wastewater treatment. A test of treating dyeing wastewater with the grafted copolymer was carried out and showed that grafting of Acrylic Acid with chitosan has a high COD removal rate 75% to the dyeing wastewater when the concentration is only 6.0 mg/L.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.
文摘对4种二烯丙基甲基烷基（n=12,14,16,18）溴化铵（标记为C12,C14,C16,C18）的性质与性能进行了研究。通过测定其热稳定性、表面活性和絮凝性能,考察产物结构对其性质与性能的影响规律。结果表明,季铵盐C12~C18的主要分解温度分别为170~300℃、172~303℃、170~293℃和170~310℃,对应失重率分别为92.8%、92.6%、96.4%和87.4%;临界胶束浓度（cmc）和临界胶束浓度下的表面张力（γcmc）分别为5.2、3.5、1.4、1.1 mmol/L和26.6、25.2、33.8、35.8 m N/m,显示出较高的表面活性;季铵盐C16的发泡与稳泡性能最好,C12的Krafft点〈0℃,C14、C16和C18的Krafft点分别为1、8和19℃;C12和C14分别对膨润土和高岭土的絮凝能力最强,表明单体的絮凝性能具有结构选择性。
文摘Graft copolymerization is one of the most attractive methods to modify natural polymers. In this study, graft copolymerization of acylic acid onto chitosan in aqueous media by ceric ammonium nitrate was investigated. The graft copolymerization reaction was carried out in a three necked flask maintained at 70＋/-0.05 ℃ under nitrogen atmosphere in a homogeneous aqueous phase （containing a small potion of acetic acid） by using ceric ammonium nitrate as an initiator. Evidence of grafting was obtained. The synthetic conditions were systematically optimized through studying the influential factors on grafting. The effectiveness of each individual factor was investigated by calculating and monitoring the variations of the grafting parameters [like monomer conversation Cm, grafting efficiency （Ge） and viscosity]. Under optimum conditions monomer conversion of 100.5% and graft efficiency of 94% were obtained, at temperature of 70℃. Flocculating ability of the copolymerization product of chitosan was studied by using Kaolin suspension as the flocculating object. And the application of the product was applied in Huayue dyeing plant. The results indicate that the higher the viscosity is, the better the flocculating ability of the copolymerization product of chitosan will be. The flocculating percentage reaches 96.0%, when the concentration of the product is only 1.0 mg/L and pH fixed at 7.0. Suitable separating mixtures for the grafted copolymer were chosen and the investigation of flocculation ability of the grafted copolymer was carried out with the aim of developing a good flocculant for wastewater treatment. A test of treating dyeing wastewater with the grafted copolymer was carried out and showed that grafting of Acrylic Acid with chitosan has a high COD removal rate 75% to the dyeing wastewater when the concentration is only 6.0 mg/L.
