两性高分子水处理剂的研究进展

本文综述了近年来国内外两性高分子水处理剂的研究进展,并对今后的研究工作提出了一些建议.     

改性天然高分子絮凝剂和聚合氯化铝复合沉降与絮体分形

在改性天然高分子絮凝剂(CMS)和聚合氯化铝(PAC)复合处理有机废水絮体沉降速度的实验中,用显微镜和电镜观察到絮凝物是有自相似特征的不规则形状,具有分形特征.在pH值为6.86、聚合氯化铝(PAC)加入量为80mg/L条件下,天然改性高分子药剂加入量为1.5mg/L时沉降效果最好,与单独加入PAC相比20min时平均沉降速度分别为2.6mm/min和1.7mm/min.并计算出此时复合处理形成絮凝体的分维数为1.70.     

交联阳离子淀粉的合成及其对重金属离子的吸附

通过正交实验合成了取代度为0．568的交联阳离子淀粉。考察了溶液pH、螯合剂用量、重金属离子初始浓度对交联阳离子淀粉去除重金属离子效果的影响。当重金属离子初始质量浓度为50mg／L、螯合剂投加量为0．5g／U时,Pb^2 ,Cu^2 ,Cr^3 在溶液pH为6时的去除率达到最高,分别为97．94％,99．46％,84．30％,而Cd^ 在溶液pH为7时的去除率达到最高,为99．36％。实验结果表明,交联阳离子淀粉是一种有效去除废水中重金属的处理剂。     

GA-g-PAMPS/AA/ST凝胶的制备及对亚甲基蓝吸附性能

采用微波辐射技术,通过接枝共聚反应制备了阿拉伯胶（GA）-g-2-丙烯酰胺-2-甲基丙磺酸（AMPS）/丙烯酸（AA）/海泡石黏土（ST）（GA-g-PAMPS/AA/ST）复合水凝胶,利用FTIR、XRD、SEM对复合水凝胶进行了表征,研究了水凝胶对水溶液中亚甲基蓝（MB）染料的吸附性能.结果显示：GA、ST和AA与AMPS发生了接枝共聚反应,形成具有均匀三维网络结构的复合水凝胶.0.025g水凝胶可以使体积为50mL、pH值为6.4、浓度为600mg/L的MB溶液的吸附量和吸附率分别达1146mg/g和95.5%,水凝胶具有较好的重复利用性能.Freundlich等温模型和准二级动力学模型能更好地描述吸附过程.热力学研究表明水凝胶对亚甲基蓝吸附是自发、吸热和不可逆的过程.该水凝胶可用作阳离子染料和阳离子型污染物的潜在候选生物质吸附剂.     

二氧化钛对地下水中砷硅的吸附及再生回用

二氧化钛(TiO_2)材料作为性能优异的吸附材料被广泛应用于地下水砷(As)的去除中.结果表明,地下水中共存硅离子(Si)会占据TiO_2的吸附位点,从而影响As的吸附及TiO_2材料的再生回用.本文通过同步辐射扩展X射线吸收精细结构(EXAFS)研究了Si对As微观吸附机制的影响,表明Si的存在不会影响As在TiO_2上的吸附构型.衰减全反射傅里叶变换红外光谱(ATR-FTIR)原位研究表明Si在TiO_2表面形成Si单体、低聚体和多聚体,从而竞争As的吸附位点,同时增加TiO_2再生的难度.为了实现TiO_2材料的高效再生,本研究进一步考察了氟化钠(NaF)对TiO_2表面Si的脱附效果,发现NaF可以有效地洗脱Si,再生后的TiO_2吸附性能稳定.ATR-FTIR光谱原位分析发现,NaF的加入可有效脱附TiO_2表面的Si单体和多聚体.当利用NaF和Na OH共同洗脱TiO_2表面的As和Si时,3次循环中As的脱附率为86.8%~100.3%,Si的脱附率为67.9%~82.0%.本研究为地下水砷硅共吸附材料的再生提供了一种有效方法.     

砷(Ⅲ)离子印迹聚合物的制备及吸附性能研究

以磁性氧化石墨烯为载体,砷离子(As(Ⅲ))为模板离子,3-巯基丙基三甲氧基硅烷(MPTS)为功能单体,正硅酸乙酯(TEOS)为交联剂合成了As(Ⅲ)离子印迹磁性氧化石墨烯纳米材料(MGO-IIP),并使用扫描电子显微镜、傅里叶变换红外光谱(FTIR)、X-射线衍射仪(XRD)和振动样品磁强计对合成材料进行了表征.同时,考察了MGO-IIP对As(Ⅲ)的吸附特性.结果表明:318 K下MGO-IIP对As(Ⅲ)的最大吸附量为148.1 mg·g~(-1),仅20 min即可达到吸附平衡,印迹因子为2.35;吸附过程服从Langmuir模型和准二级动力学模型,说明是自发的吸热过程;在其他干扰离子存在的情况下,MGO-IIP对As(Ⅲ)仍然具有良好的吸附效果,且能够重复使用4次,在含砷废水处理中具有应用价值.MGO-IIP材料对As(Ⅲ)的吸附机制为表面络合作用及物理吸附.     

两性高分子螯合絮凝剂与Cu(Ⅱ)、Pb(Ⅱ)、Cd(Ⅱ)、Ni(Ⅱ)的螯合稳定性

采用紫外分光光度法测定了两性高分子螯合絮凝剂(ACPF)与Cu2+、Cd2+、Pb2+、Ni2+形成螯合物的吸收光谱,考察了螯合沉淀物的稳定性,探讨了螯合物的组成,并计算其稳定常数.结果表明,ACPF分别在204、251和285 nm处出现最大吸收峰;ACPF中—CSS-基团与Cu2+、Pb2+、Cd2+和Ni2+等离子均按物质的量比2:1形成稳定螯合物,分别在319、310、313.5和326 nm处出现最大吸收峰,最大吸收峰发生显著红移.ACPF与Cu2+、Pb2+、Cd2+和Ni2+形成的螯合物的稳定常数分别为1.37 ×1012、3.26 ×1011、2.05×1011和3.04×1010.螯合沉淀物中重金属离子的溶出率随溶出液pH值升高而降低.PH≥5.6时,ACPF-Cu2+、ACPF-Ni2+ 、ACPF-Pb2+和ACPF-Cd2+都很稳定,浸出60.D后溶出液中Cu2+、Ni2+、Pb2+和Cd2+浓度都分别低于相应的国家污水综合排放标准(GB8979-1996).     

木质素基吸附材料的制备及其吸附性能研究

以木质素磺酸盐为原料,利用反相悬浮聚合技术,成功制备木质素基吸附材料,并研究了交联剂用量、分散剂用量、聚合温度、聚合时间及体系酸度等对悬浮聚合反应及其阳离子染料亚甲基蓝吸附性能的影响。实验结果表明,所制备的吸附材料对亚甲基蓝有较快的吸附速度和较高的吸附量,当木质素吸附材料对亚甲基蓝的吸附量达到17.71mg/g后,吸附趋向饱和,温度保持在30℃左右有较高的吸附量。     

Hydrolyzed Al(Ⅲ) clusters: Speciation stability of nano-Al13

Pure nano-Al13 and aggregates at various concentrations were prepared to examine the particle size effect of coagulation with inorganic polymer fiocculant. The property and stability of various species formed were characterized using Infrared, 27Al-NMR,photo correlation spectroscopy (PCS), and Ferron assay. Results showed that concentration and temperature exhibited different roles on the stability of Al13. The quantity of Alb species analyzed by ferron assay in the initial aging period corresponded well with that of Al13, which has been confirmed in a dimension range of 1-2 nm by PCS. Al13 solutions at high concentrations (0.5-2.11 mol/L)were observed to undergo further aggregation with aging. The aggregates with a wide particle size distribution would contribute to the disappeared/decreased Al13 basis on the 27Al-NMR spectrum, whereas a part of Al13 would still remain as Alb. At low concentrations,Al13 solution was quite stable at normal temperature, but lost its stability quickly when heating to 90°C.     

Adsorptive removal of hydrophobic organic compounds by carbonaceous adsorbents: A comparative study of waste-polymer-based, coal-based activated carbon, and carbon nanotubes

Adsorption of the hydrophobic organic compounds (HOCs) trichloroethylene (TCE), 1,3-dichlorobenzene (DCB), 1,3-dinitrobenzene (DNB) and γ-hexachlorocyclohexane (HCH) on five different carbonaceous materials was compared. The adsorbents included three polymer-based activated carbons, one coal-based activated carbon (F400) and multiwalled carbon nanotubes (MWNT). The polymerbased activated carbons were prepared using KOH activation from waste polymers: polyvinyl chloride (PVC), polyethyleneterephthalate (PET) and tire rubber (TR). Compared with F400 and MWNT, activated carbons derived from PVC and PET exhibited fast adsorption kinetics and high adsorption capacity toward the HOCs, attributed to their extremely large hydrophobic surface area (2700 m²/g) and highly mesoporous structures. Adsorption of small-sized TCE was stronger on the tire-rubber-based carbon and F400 resulting from the pore-filling effect. In contrast, due to the molecular sieving effect, their adsorption on HCH was lower. MWNT exhibited the lowest adsorption capacity toward HOCs because of its low surface area and characteristic of aggregating in aqueous solution.