应用强化混凝过程控制水中的剩余腐殖酸与残留铝

为达到最大的腐殖酸去除和最小的铝残留,采用了强化混凝技术,研究了各因素对混凝过程的影响.实验结果表明,在20℃,pH为6～6.5,AlCl₃投加量为0.5×10^-3mol/L的条件下,控制水中的剩余腐殖酸在0.04 cm^-1以下,并能同时有效控制残留铝在0.1 mg/L左右.加入0.01 mol/L的CaCl₂对混凝效果有一定的促进作用.同时由于原水中悬浮颗粒随季节变化,模拟了不同投量的高岭土对腐殖酸去除过程的影响.     

黄浦江水源的溶解性有机物分子量分布变化的特点

通过一年时间对黄浦江上游水进行有机物分子量分布的测定，表明黄浦江有机物分子量分布的变化受湖泊水质和排入污水的共同影响，其主要特征是溶解性的低分子量有机物占多数，黄浦江水中的腐殖酸含量和三氯甲烷生成潜能在夏季时最高，冬季时最低。     

水体中汞的转化与毒性

本文分析了自然水体中汞的存在形式,揭示了不同水体中PH、Cl-和腐殖酸浓度的变化对汞存在形式的影响,定量分析了甘汞、氢氧化汞、腐殖酸汞的毒性,提出了综合评价水体中汞化合物毒性的计算方法和分析方法.     

灭草松在腐殖酸上的吸附及其机理

通过吸附动力学、吸附等温线和IR，ESR技术，研究了腐殖酸对灭草松的吸附及吸附机理，并且对pH、离子强度对吸附过程的影响进行了探讨。结果表明灭草松在腐殖酸上经过大约4h的初始快速阶段，此后进入慢速吸附过程。溶液pH可能会影响腐殖酸的构型。高pH时，吸附量随溶液离子强度增加稍有增加。灭草松在腐殖酸上的吸附过程中存在氢键、电荷转移作用，疏水分配也是可能存在的机理。     

聚硫酸铁强化混凝除锑(V)作用机制探讨

以聚硫酸铁(PFS)为絮凝剂,考察强化混凝去除饮用水源水中五价锑(Sb(V))时原水pH值、PFS投量、共存阴离子(HCO3－和PO43－)及腐殖酸(HA)等对其去除效果影响及作用机制.结果表明,原水pH值对强化混凝过程Sb(V)存在形态及PFS的水解产物有重要影响,表现为较低pH值和较高PFS投量均有利于提高Sb(V)的去除率;由于竞争吸附作用的存在,共存阴离子与HA均对Sb(V)的混凝去除产生负面效应.此外, PFS除Sb(V)过程较为符合准二级动力学模型.     

Relationships between humic substance-bound mercury contents and soil properties in subtropical zone

The bioavailability of humic substance-bound mercury （HS-Hg） has been established, while the distribution of HS-Hg in soils in relation to soil properties remains obscure. Path analysis and principal component analysis were employed in present study to investigate how soil factors influence the contents of HS-Hg in soils. Results showed that HS-Hg ranged from 0.0192 to 0.2051 mg/kg in soils. The two fractions existed in soils as humic acid-bound mercury （HA-Hg） 〉 fulvic acid-bound mercury （FA-Hg） and the ratio of HA-Hg/FA-Hg was 1.61 on the average. Soil organic carbon （OC） and HS favorably determined soil HS-Hg and the two fractions. The mercury source forming HS-Hg derived from soil total mercury and HS-Hg. FA-Hg and HA-Hg served as mercury source for each other. In acidic soils, FA-Hg and HA-Hg consistently rose with the increase of OC, and generally HA-Hg increased more dramatically. Soils with lower pH and lighter texture contained more HS-Hg, particularly fraction of FA-Hg. Among all influencing factors, organic material source showed the strongest effect, followed by other soil properties and soil mercury source.     

腐殖酸对铊污染土壤中铊形态和分布的影响

选用云浮含铊硫铁矿周围冲积土壤为供试样品,在土样中投加不同比例腐殖酸,采用连续浸提法对比研究了外源腐殖酸对受铊污染土中的铊不同形态及活性的影响.结果表明:随腐殖酸投入比的加大,酸可交换态含量明显下降,Fe/Mn氧化物结合态反之,有机质结合态与Fe/Mn氧化物结合态雷同,残余态几乎无变化;腐殖酸对酸可交换态铊分配比率最高为13.6%～30.5%,分别是有机态铊和Fe/Mn氧化态铊的2.8～15.1倍和2.8～3.7倍.结果说明腐殖酸有降低冲积土壤上有害活动态铊的功能,其作用机制在于腐殖酸具备的络合(螯合)能力和胶体特性.研究确认,腐殖酸可作为土壤重金属污染修复的优质材料.     

Pahokee泥炭腐殖酸的相对分子量分布特征及其对菲的吸附影响

使用切面流超滤方法,将Pahokee泥炭中分离出的腐殖酸分为具有不同相对分子质量的8个级分(UF1:<1k;UF2:1～3k;UF3:3～5k;UF4:5～10k;UF5:10～30k;UF6:30～50k;UF7:50～100k:UF8:>300k),表明该泥炭中的腐殖酸主要分布于几个高相对分子量级分中(UF5,UF6和UF8),可占所提取的腐殖酸质量的83 5%.体积排阻色谱的流出曲线说明可以通过超滤手段将腐殖酸这种复杂的、非均匀性的大分子物质分成相对均一的、窄相对分子量分布的分子.而两种方法所测相对分子量的差异可能与两个操作系统间不同的操作条件有关.各超滤级分的腐殖酸对菲的吸附实验说明相对分子量是影响腐殖酸吸附的一个重要参数;随相对分子量的增加,腐殖酸对菲的吸附及其非线性特征均增强.     

Adsorption characteristics of humic acid-immobilized amine modified polyacrylamide/bentonite composite for cationic dyes in aqueous solutions

Humic acid-immobilized amine modified polyacrylamide/bentonite composite (HA-Am-PAA-B) was prepared and used as an adsorbent for the adsorption of cationic dyes (Malachite Green (MG), Methylene Blue (MB) and Crystal Violet (CV)) from aqueous solutions. The polyacrylamide/bentonite composite (PAA-B) was prepared by intercalative polymerization of acrylamide with Nabentonite in the presence of N,N0-methylenebisacrylamide as a crosslinking agent and hexamethylenediammine as propagater. PAA-B was subsequently treated with ethylenediammine to increase its loading capacity for HA. The surface characterizations of the adsorbent were investigated. The adsorbent behaved like a cation exchanger and more than 99.0% removal of dyes was detected at pH range 6.0–8.0. The capacity of HA-Am-PAA-B was found to decrease in the following order: MG > MB > CV. The kinetic and isotherm data were interpreted by pseudo-second order rate equation and Freundlich isotherm model, respectively. Experiments were carried out using binary solute systems to assess the competitive adsorption phenomenon. The experimental isotherm data for each binary solute combination of MG, MB and CV were analyzed using Sheindrof-Rebhun-Sheintuch (SRS) (multicomponent Freundlich type) equation.