Reversibly enhanced aqueous solubilization of volatile organic compounds using a redox-reversible surfactant

Surfactant-enhanced remediation (SER) is an effective method for the removal of volatile organic compounds (VOCs) from contaminated soils and groundwater. To reuse the surfactant the VOCs must be separated from the surfactant solutions. The water solubility of VOCs can be enhanced using reversible surfactants with a redox-acive group, (ferrocenylmethyl)dodecyldimethylammonium bromide (Fcl2) and (ferrocenylmethyl)tetradecanedimethylammonium bromide (Fcl4), above and below their critical micelle concentrations (CMC) under reducing (I⁺) and oxidative (I²⁺) conditions. The CMC values of Fcl2 and Fcl4 in I⁺ are 0.94 and 0.56 mmol/L and the solubilization of toluene by Fcl2 and Fcl4 in I⁺ for toluene is higher than the solubilization achieved with sodium dodecyl sulfate, cetyltrimethylammonium bromide and Trition X-114. The solubilization capacity of the ferrocenyl surfactants for each tested VOCs ranked as follows: ethylbenzene > toluene > benzene. The solubilities of VOCs by reversible surfactant in I⁺ were 30% higher than those in I²⁺ at comparable surfactant concentrations. The effects of Fcl4 concentrations on VOCs removal efficiency were as follows: benzene > toluene > ethylbenzene. However, an improved removal efficiency was achieved at low ferrocenyl surfactant concentrations. Furthermore, the reversible surfactant could be recycled through chemical approaches to remove organic pollutants, which could significantly reduce the operating costs of SER technology.     

Adsorptive property of Cu^2＋-loaded montmorillonite clays for Escherichia coli K_（88） in vitro

The Cu²⁺-loaded montmorillonite clays (MMT-Cu) may be a good material for the adsorbed and eliminated pathogenic bacteria from aqueous solution.     

Evaluation of reusing alum sludge for the coagulation of industrial wastewater containing mixed anionic surfactants

A coagulation-flocculation process is typically employed to treat the industrial wastewater generated by the consumer products industry manufacturing detergents, soaps, and others. The expenditure of chemicals including coagulants and chemicals for pH adjustment is costly for treating this wastewater. The objective of this study was to evaluate the feasibility of reusing the aluminum sulfate (alum) sludge as a coagulant or as a coagulation aid so that the fresh alum dosage can be minimized or the removal e ciency can be enhanced. The experiments were conducted in a jar-test apparatus simulating the coagulation-flocculation process for simultaneous removals of organic matters, anionic surfactants, suspended solids, and turbidity. At the optimum initial pH value of 10 and the fresh alum concentration of 400 mg/L, the total suspended solids (TSS), total chemical oxygen demand (TCOD), total anionic surfactants, and turbidity removal e ciencies were 71.5%, 76.4%, 95.4%, and 98.2%, respectively. The addition of alum sludge as a coagulant alone without any fresh alum addition could significantly remove the turbidity, TCOD, and anionic surfactants. The TSS was left in the supernatants after the settling period, but would subsequently be removed by adding the fresh alum. The TSS, TCOD, and turbidity removal e ciencies were also enhanced when both the alum sludge and the fresh alum were employed. The TCOD removal e ciency over 80% has been accomplished, which has never fulfilled by using the fresh alum alone. It is concluded that the alum sludge could be reused for the treatment of industrial wastewater generated by the consumer products industry.     

化学沉淀法处理线路板厂络合铜废水实验研究

为解决某线路板厂络合铜废水达标排放的问题,模拟该厂络合铜废水处理的工艺条件,采用硫酸亚铁和硫化钠相结合的化学沉淀法进行小试,通过正交实验确定最佳药剂投加量.结果表明,影响络合铜废水处理效果的各因素的重要性顺序依次为pH、PAM、FeSO4·7H2O、LIME、Na2S;处理500mL络合铜废水的最佳的操作条件是废水初始...     

一株产生物表面活性剂菌株的筛选

从被长期受石油污染的特定环境中取样,经富集培养和平板法筛选得到9株乳化性能较好的菌株.采用排油圈法对这9株菌进行表成活性测定,其中菌株SF-6表面活性最强,通过形态观察和部分生理生化试验初步鉴定该菌株为铜绿假单胞菌(Pseudomonas Aeruginosa),其所产生物表面活性物质初步鉴定为鼠李糖脂.     

土壤阴离子表面活性剂总量亚甲基蓝法研究

文章通过设计正交试验,针对提取的主要因素提取液配比、提取时间、提取温度和提取剂用量确定最优的前处理方法,建立与国标《水质阴离子表面活性剂亚甲基蓝分光光度法》(GB7494-87)对应的土壤阴离子表而活性剂(LAS)的亚甲基蓝分光光度法.土壤样品烘干后经20 mL乙醇水溶液(70％)提取,水浴恒温振荡仪45℃下振荡2h,...     

产表面活性剂根际菌协同龙葵修复镉污染土壤

从某矿区重金属污染的土壤中分离筛选出一株能产生物表面活性剂的根际细菌LKS06,经生理生化特征及16S rDNA序列分析,将其鉴定为假单孢菌属(Pseudomonas sp.LKS06).生物学特性的测定表明,菌株LKS06对多种重金属有很高的耐受性,且具有分泌吲哚乙酸、产铁载体和ACC脱氨酶活性的能力,并对土壤重金属...     

有关斜管沉淀池的上升流速讨论

文章从理论上了分析斜管沉淀池上升流速对沉淀池处理效果的影响,及原水特性与斜管沉淀池上升流速取值的关系。讨论分析斜管沉淀池设计时,应根据原水特性不同选择不同的斜管沉淀池上升流速。     

水力负荷对辐流式初沉池污染物去除效果的影响

以沉砂池出水为原水,在沉淀试验研究颗粒截留速度u0基础上,通过动态试验考察水力负荷对辐流式初沉池污染物去除效果的影响。研究结果表明无机悬浮固体(FSS)分离和总悬浮固体(TSS)高效去除的颗粒截留速度u0分别为0.025 m/min和0.05 m/min。由于泥层截留作用,水力负荷qA在46.3 m3/(m2.d)时,辐流式初沉池污染去除最高效,TSS、总氮(TN)和总磷(TP)去除率分别达到81%,23%,59%。     

聚合氯化铝-腐殖酸(PACl-HA)絮体的物理与分形特征研究

采用低温急速冷冻-真空干燥技术制备了PACl-HA絮体的粉末样品,研究了这些样品的物理与分形特征.结果表明,PACl-HA絮体具有无定形结构,主要组成元素为C、O、Al,所含特征官能团保留了絮体组成原料的一些特征;絮体的BET比表面积为130～161 m²·g^-1,BJH累积吸附孔体积为0.38～0.52 cm³·g^-1,BJH脱附平均孔径为7.7～9.6nm,PSD峰值对应孔径8.4～11.2nm.PACl-HA絮体具有自相似性的粗糙表面,呈现多尺度分形特征;图象法和N₂吸附/脱附等温线法确定的表面分形维数Ds分别为2.03～2.26、2.24～2.37,前者的分形尺度大约处于23～390nm之间,主要属于絮体外表面尺度,而后者的分形特征尺度区间的下限大约为0.2nm,属于孔表面尺度;另外,对同一絮体,N₂吸附法和脱附法确定的孔表面分形维数不同.热力学模型计算出的D_s远大于3,与Sahouli等的研究不符.