绿色水处理剂-改性聚天冬氨酸的制备及其缓蚀性能研究

聚天冬氨酸（PASP）是一种环境友好的新型阻垢缓蚀剂,为了增强它的缓蚀性能,对其进行改性研究。利用四种不同的有机胺对聚天冬氨酸的前驱体聚琥珀酰亚胺进行开环,并考察其改性产物缓蚀性能。研究结果表明：选择以熔融聚合法所得的前驱体聚琥珀酰亚胺为母体,以乙醇胺对其进行开环;且当PSI为3 g,乙醇胺用量1.8 ml时,温度25℃,反应时间60 min,在2 400 rpm搅拌速度下获得改性PASP产品的缓蚀效果最佳。     

AA-HPA-AMPS阻垢剂最佳合成条件研究

通过溶液聚合方法,以丙烯酸、丙烯酸羟丙酯、2-丙烯酰胺-2-甲基丙磺酸为单体,以过硫酸铵为引发剂,合成AA-HPA-AMPS聚合物。固定聚合物浓度为4mg/L,分别考查反应时间、反应温度(X1)、引发剂用量(X2)、单体配比(X3)对聚合物阻CaCO3垢性能的影响,并设计了正交实验,得出聚合物在90℃、引发剂用量为13.5%、M(AA)∶M(HPA)为7∶3时,阻CaCO3垢率最高为80.9%。为探究此聚合物是否有更高的阻垢性能,应用多元回归分析对正交实验结果进行分析及验证,聚合物阻CaCO3垢效率y与各影响因素x之间基本满足y=-146.825+16.25x2,最佳聚合条件为X2=14.5,y为90.20%。     

鼓泡法对聚天冬氨酸阻垢性能的评价

用鼓泡法对六种聚天冬氨酸 (Polyasparticacid ,PASP)的阻碳酸钙垢性能进行了评价 ,考察了pH值、阻垢剂用量、温度、恒温时间等对阻垢性能的影响。研究发现 ,阻垢率随着聚天冬用量的增加而增大 ,其用量在 1 0mg/L时 ,已能获得较好的阻垢效果。另外 ,与聚丙烯酸 (PAA)和聚马来酸 (HPMA)的比较发现 ,聚天冬在高温水系统中作长时间停留 ,仍对碳酸钙垢有较强的抑制作用     

柠檬酸改性聚天冬氨酸阻垢剂的合成及性能研究

将柠檬酸、马来酸酐、氨共聚,在主链上引入羧基以改性聚天冬氨酸,提高了其阻垢性能。实验测定了不同反应条件下产品的阻垢性能,讨论了聚天冬氨酸共聚物的合成工艺条件。结果表明n(氨):n(MA):n(柠檬酸)=2.2:1:0.09,胺化时间2.5h,热聚温度170℃,热聚时间15min,合成的PASP共聚物用量为2mg/L时产品的阻垢效果最好。     

熔融法合成新型磺酸基聚合物MA/SAS

在催化剂超强酸SO2-4/ZnO的作用下,以马来酸酐和烯丙基磺酸钠为原料,采用直接熔融合成了新型磺酸基聚合物(MA/SAS),通过单因素试验和正交试验,探讨了其合成工艺条件。同时对聚合物进行IR和差热-热重表征,采用电子显微镜考察了聚合物对CaCO3垢形的影响并探讨了其阻垢机理。试验结果表明:新型磺酸基聚合物具有良好的热稳定性和良好的阻CaCO3垢性能,对CaCO3垢既具有较强的分散作用又具有明显的晶格畸变能力。     

PASP、PAA与PBTCA阻垢性能的对比实验研究

采用静态阻垢法研究了聚天冬氨酸(PASP)、聚丙烯酸(PAA)和2-膦酸基丁烷-1,2,4-三羧酸(PBTCA)对碳酸钙和硫酸钙的阻垢性能,并用旋转挂片法研究了3种阻垢剂作用下湿法石灰脱硫浆液系统的结垢规律.研究发现:随着阻垢剂浓度的增加,3种阻垢剂都表现出溶限效应;相同实验条件下,3种阻垢剂对碳酸钙的静态阻垢性能表现为PBTCA>PAA>PASP;对中性和碱性环境,pH对阻垢剂阻硫酸钙垢的性能影响较小;随着温度的升高和反应时间的延长,3种阻垢剂阻硫酸钙的阻垢率先增大后减小;对湿法石灰脱硫浆液系统,3种阻垢剂作用下,单位面积挂片上的结垢量均是随着阻垢剂质量浓度的增大先增大后减小,在浓度达到30mg/L时,挂片上的结垢量都很小.     

阳离子絮凝剂P(AM-DAC)的合成、表征及应用

以丙烯酰胺(AM)和丙烯酰氧乙基三甲基氯化铵(DAC)为单体,过硫酸钾(KPS)为引发剂,通过水溶液聚合的方法合成了阳离子絮凝剂P(AM-DAC)。探讨了单体配比、单体浓度、引发剂用量、反应时间、反应温度等因素对阳离子聚丙烯酰胺(CPAM)主要性能的影响。实验得出了较佳的反应条件:聚合温度为70℃,引发剂用量为0.16%,单体配比m(AM):m(DAC)=1:8,总单体浓度为20%,反应时间3 h。在上述条件下,所得阳离子聚丙烯酰胺絮凝剂的特性黏数为18.692 4 dL/g,在其加入量为0.003%的条件下处理巡司河污水,上层清液透光率达90.7%,污泥脱水率达89.2%。并对该聚合物絮凝剂的结构和热行为进行了表征。     

反相乳液法合成瓜尔胶丙烯酰胺接枝共聚物

文章以液体石蜡为油相,以一定质量分数的瓜尔胶水溶液为水相,以Span80-OP-10为复合乳化剂,以十六十八醇为助乳化剂,制备了稳定的反相乳液。研究了物料比、反应温度、反应时间、引发剂的浓度对聚合物转化率、接枝率的影响,得到较好的聚合条件为∶m(GG)∶m(AM)为1∶4、反应时间为5 h、反应温度为45℃、引发剂浓度为5 mmol时,聚合物的接枝率和转化率达到最大值,分别为67%、48%。此条件下的接枝聚合物分子量达到最大值为4.1×106。并且对聚合物进行了红外表征,表明单体已经接枝成功。聚合物性能测定表明接枝聚合物具有较好的耐温性能和絮凝性能,有望作为一种新型絮凝剂应用在污水处理中。     

固体超强酸催化合成PESA及其阻垢性能研究

以马来酸酐为原料、首次应用固体超强酸SO_4~(2-)/M_xO_y为催化剂"一锅法"催化合成聚环氧琥珀酸(PESA)。采用FTIR、GPC对产物结构和分子量进行了表征,利用SEM、XRD考察了产物对Ca CO_3沉渣形貌和物相,并探讨了其阻垢机理。结果表明:8种固体超强酸SO_4~(2-)/M_xO_y中SO_4~(2-)/Ti O_2-Si O_2催化活性最好,阻垢效率高达98.87%;FTIR分析证实了产物分子结构具有羟基、羧基、C-O-C基团,聚合物为PESA;GPC分析该PESA的数均和重均相对分子量分别为1 471和1 609;SEM和XRD分析表明该PESA能有效地损伤和变形Ca CO_3沉渣的晶体习性和结构,表现了明显的晶格畸变能力。     

表面活性物质对HPMA阻垢缓蚀性能的影响

表面活性物质的加入可明显提高水解聚马来酸酐(HPMA)的阻垢、缓蚀性能,且不同表面活性物质影响程度不同,通过剩余硬度法测定阻垢性能,静态失重法测定缓蚀性能,从而比较异丙醇、葡萄糖酸钠对HPMA阻垢、缓蚀性能的影响。实验结果表明,异丙醇与HPMA复合使用时效果较好,阻垢率达到 79 0 %,缓蚀率达 70 7%,且阻垢率随Ca2 + 浓度增大而增大。     

Evaluation of phytoextracting cadmium and lead by sunflower, ricinus, alfalfa and mustard in hydroponic culture

Soil contaminated with heavy metals cadmium(Cd)and lead(Pb)is hard to be remediated.Phytoremediation may be a feasible method to remove toxic metals from soil,but there are few suitable plants which can hyperaccumulate metals.In this study,Cd and Pb accumulation by four plants including sunflower(Helianthus annuus L.),mustard(Brassica juncea L.),alfalfa(Medicago sativa L.), ricinus(Ricinus communis L.)in hydroponic cultures was compared.Results showed that these plants could phytocxtract heavy metals, the ability of accumulation differed with species,concentrations and categories of heavy metals.Values of BCF(bioconcentration factor)and TF(translocation factor)indicated that four species had dissimilar abilities of phytoextraction and transportation of heavy metals.Changes on the biomass of plants,pH and Eh at different treatments revealed that these four plants had distinct responses to Cd and Pb in cultures.Measurements should be taken to improve the phytoremediation of sites contaminated with heavy metals,such as pH and Eh regulations,and so forth.     

Oxidation of As(Ⅲ) by potassium permanganate

The oxidation of As(Ⅲ) with potassium permanganate was studied under conditions including pH, initial As(Ⅲ) concentration and dosage of Mn(Ⅶ). The results have shown that potassium permanganate was an effective agent for oxidizing of As(Ⅲ) in a wide pH range. The pH value of tested water was not a significant factor affecting the oxidation of As(Ⅲ) by Mn(Ⅶ). Although theoretical redox analyses suggest that Mn(Ⅶ) should have better performance in oxidization of As(Ⅲ) within lower pH ranges, the experimental results show that the oxidation efficiencies of As(Ⅲ) under basic and acidic conditions were similar, which may be due to the adsorption of As(Ⅲ) on the Mn(OH)2 and MnO2 resulting from the oxidation of As(Ⅲ).     

Distribution and ecological effect of mercury in Laogang landfill, Shanghai, China

Laogang landfill near Shanghai is the largest landfill in China, and receives about 10000 t of daily garbage per day, Samples of topsoil and plants were analyzed to evaluate mercury pollution from the landfill. For topsoil samples, there were significant correlations among total mercury （HgT）, combinative mercury （Hgc） and gaseous mercury （HgG）, and content of total organic carbon （TOC）, but, no significantly relationship was found between Hg content and filling time. Hg content changes in vertical profiles with time showed that the average Hgv of profiles 1992, 1996, and 2000 was similar, but their average HgG was quite different. HgT was significantly correlated with Hgc in profile 1992 and 2000, and Hgv was significantly correlated with Hg6 in profile 1996. HgG/Hgv ratio in profile samples decreased in the order of （HgG,/HgT）1992〉（HgG/HgT）1996〉〉（HgG/HgT）2000. A simple outline of Hg release in landfill could be drawn： with increasing of filling time, degradation undergoes different biodegradation, accordingly, gaseous mercury goes through small, more, and small proportion to total mercury. Distribution of Hg in plants was inhomogeneous, following the order of leaf〉root〉stem. The highest value of leaf may be associated with higher atmospheric Hg from landfill. Ligneous plants （e.g. Phyllostachys glanca, Prunus salicina and Ligustrum lucidum） are capable of enriching more Hg than herbaceous plants.     

EDTA-enhanced phytoremediation of lead contaminated soil by Bidens maximowicziana

Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils.Bidens maximowicziana is a new Pb hyperaccumulator,which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb.The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues.The Pb distribution order in the B. maximowicziana was:leaf>stem>root.The effect of amendments on phytoremediation was also studied.The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application.Compared with CK(control check),EDTA application promoted translocation of Pb to overground parts of the plant.The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg.This research demonstrated that B.maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil,especially,combination with EDTA.     

Decomposition of alachlor by ozonation and its mechanism

Decomposition and corresponding mechanism of alachlor, an endocrine disruptor in water by ozonation were investigated. Results showed that alachlor could not be completely mineralized by ozone alone. Many intermediates and final products were formed during the process, including aromatic compounds, aliphatic carboxylic acids, and inorganic ions. In evoluting these products, some of them with weak polarity were qualitatively identified by GC-MS. The information of inorganic ions suggested that the dechlorination was the first and the fastest step in the ozonation of alachlor.     

Enzymatic oxidation of aqueous pentachlorophenol

The influence of the nonionic surfactant Tween 80 on pentachlorophenol （PCP） oxidation catalyzed by horseradish peroxidase was studied. The surfactant was tested at concentrations below and above its critical micelle concentration （CMC）. Enhancement of PCP removal was observed at sub-CMCs. The presence of Tween 80 in the reaction mixture reduced enzyme inactivation which occurred through a combination of free radical attack and sorption by precipitated products. A simple first-order model was able to simulate time profiles for enzyme inactivation in the presence or absence of Tween 80. At supra-CMCs, the surfactant caused noticeable reductions in PCP removal, presumably through micelle partitioning of PCP which precluded the hydrophobic PCP molecule from interacting with the enzyme.     

Chlorobenzenes in waterweeds from the Xijiang River （Guangdong section） of the Pearl River

The Xijiang River is the major source of water for about 4.5 millions of urban population and 28.7 millions of rural population. The water quality is very important for the health of the rural population. The concentration and distribution of chlorobenzenes (CBs) in both water and waterweeds collected from 4 stations in the Xijiang River (Gangdong section) of the Pearl River in April and November were determined. The result showed that nearly every congener of CBs was detected. The total contents of CBs (∑CBs) in the river water ranged from 111.1 to 360.0 ng/L in April and from 151.9 to 481.7 ng/L in November, respectively. The pollution level of CBs in the water in April was higher than that in November. The contents of ∑ CBs in waterweeds ranged from 13.53×102 μg/g to 38.27×102μg/g dry weight (dw). There was no significant difference between April and November in waterweeds. The distribution of CBs in roots, caulis, and leaves of Vallisneria spiralis L. showed different patterns. The leaves mainly contained low-molecular-weight CBs(DCBs), whereas the roots accumulated more PCBs and HCBs. The average lgBCFlip (bioconcentration factor) of CBs ranged from 0.64 to 3.57 in the waterweeds. The spatial distribution character of CBs in the Xijiang River was: Fengkai County ＜ Yunan County ＜Yun'an County ＜ Gaoyao County according to the ∑CBs, and the pollution deteriorated from the upstream to the downstream of the Xijiang River. Further analysis demonstrated that the discharge of waste containing CBs may be the main source of CBs pollution in the Xijiang River.     

Degradation of 2,4-dichlorophenol with a novel TiO2/Ti-Fe-graphite felt photoelectrocatalytic oxidation process

Degradation of 2,4-dichlorophenol(2,4-DCP)was studied in a novel three-electrode photoelectrocatalytic(PEC)integrative oxidation process,and the factors influencing the degradation rate,such as applied current,flow speed of O_2,pH,adscititious voltage and initial 2,4-DCP concentration were investigated and optimized.H_2O_2 was produced nearby cathode and Fe~(2 )continuously generated from Fe anode in solution when current and O_2 were applied,so,main reactions,H_2O_2-assisted TiO_2 PEC oxidation and E-Fenton reaction,occurred during degradation of 2,4-DCP in this integrative system.The degradation ratio of 2,4-DCP was 93% in this integrative oxidation process,while it was only 31% in E-Fenton process and 46% in H_2O_2-assisted TiO_2 PEC process.So,it revealed that the degradation of 2,4-DCP was improved greatly by photoelectrical cooperation effect.By the investigation of pH,it showed that this integrative process could work well in a wide pH range from pH 3 to pH 9.     

Effect of copper on the degradation of pesticides cypermethrin and cyhalothrin

The influence of coexisting copper (Cu) ion on the degradation of pesticides pyrethroid cypermethrin and cyhalothrin in soil and photodegradation in water system were studied.Serial concentrations of the pesticides with the addition of copper ion were spiked in the soil and incubated for a regular period of time,the analysis of the extracts from the soil was carried out using gas chromatography (GC).The photodegradation of pyrethroids in water system was conducted under UV irradiation.The effect of Cu~(2 ) on the pesticides degradation was measured with half life (t_(0.5)) of degradation.It was found that a negative correlation between the degradation of the pyrethroid pesticides in soil and Cu addition was observed.But Cu~(2 ) could accelerate photodegradation of the pyrethroids in water.The t_(0.5) for cyhalothrin extended from 6.7 to 6.8 d while for cypermethrin extended from 8.1 to 10.9 d with the presence of copper ion in soil.As for photodegradation,t_(0.5) for cyhalothrin reduced from 173.3 to 115.5 rain and for cypermethrin from 115.5 to 99.0 min.The results suggested that copper influenced the degradation of the pesticides in soil by affecting the activity of microorganisms.However, it had catalyst tendency for photodegradation in water system.The difference for the degradation efficiency of pyrethroid isomers in soil was also observed.Copper could obviously accelerate the degradation of some special isomers.     

基于综合水质标识指数和对应分析法的校园河道水质评价

以三峡大学的校园河道求索溪为研究对象,利用综合水质标识指数法确定求索溪水质类别,分析其水质时空变化规律,并利用对应分析法得出求索溪中不同监测点的主要污染因子.研究结果表明:求索溪整体的综合水质标识指数为7.423,整体水质为劣V类(地表水环境质量标准GB 3838-2002)且黑臭.从时间变化来看,求索溪4月份的水质最差,5月份次之,4、5月份所有监测点的水质都劣于V类且黑臭;8月份水质最好,水质为Ⅳ类;从空间分布来看,8个监测点综合水质标识指数均超过6.0,水质为劣V类,其中6号监测点的水质相对最好,监测点3号的水质相对最差;对应分析法得出求索溪的整体水体污染程度受总氮因子的影响最大,其次为总磷.该研究拟为求索溪及类似校园河道的水环境治理研究提供基础依据和参考.