重金属离子对酵母降解苯酚的影响

研究了铜、镉、锌和铅对酵母 (Pityrosporumsp .)降解苯酚的影响 .急性毒性试验表明 :Cu2 36h时对菌体生物量的毒性抑制微低于对苯酚降解的抑制 ;48h时对菌体生物量的毒性高于对苯酚降解的毒性 .受试时间段 ,Cd2 对菌体生物量的毒性均高于其对苯酚降解的毒性 .在 0— 36h内 ,Cu2 对菌体比增长速率的EC50 是 45 0nmol·l- 1 ,对苯酚降解速率的EC50 是 0 32nmol·l- 1 ;Cd2 相应的EC50 分别是 681nmol·l- 1 和 33 3nmol·l- 1 .Cu2 比Cd2 具有更高的毒性 .而锌和铅在低浓度时 ,对酵母降解苯酚过程中菌体生物量以及苯酚的降解均有促进作用 ,其促进作用随着金属离子浓度的增加而减弱 .     

Ca(Ⅱ)在活性污泥生物絮凝中的作用研究

采用4个平行的序批式反应器(SBR),研究了进水Ca2+浓度对活性污泥絮体表而特性和结构稳定性的影响,并由此来确定Ca2+在生物絮凝中的作用.结果表明:随着进水Ca2+浓度的增加,污泥中的Ca含量逐渐增大.进水中Ca2+的加入,增大了污泥絮体的粒径和密度,进南改善了污泥的沉降性能;Ca2+的加入,使可供结合的蛋白质数量最高增至近1倍,污泥表面疏水性也相应增强;污泥絮凝性能的改善,主要和可供Ca2+结合的蛋白质含量增加有关,而非多糖;EDTA通过络合污泥絮体中的Ca2+,破坏了山Ca2+架桥形成的污泥絮体结构,这说明Ca2+可通过和胞外聚合物(extracellular polymeric substances,EPS)中的负电官能团架桥来促进污泥絮体的形成并维持絮体结构的稳定性.     

Surface reaction of Bacillus cereus biomass and its biosorption for lead and copper ions

In this study, the surface chemical functional groups of Bacillus cereus biomass were identified by Fourier transform infrared （FTIR） analytical technique. It had been shown that the B. cereus cells mainly contained carboxyl, hydroxyl, phosphate, amino and amide functional groups. The potentiometric titration was conducted to explain the surface acid-base properties of aqueous B. cereus biomass. The computer program FITEQL 4.0 was used to perform the model calculations. The optimization results indicated that three sitesthree pKas model, which assumed the cell surface to have three distinct types of surface organic functional groups based on the IR analysis results, simulated the experimental results very well. Moreover, batch adsorption experiments were performed to investigate biosorption behavior of Cu（Ⅱ） and Pb（Ⅱ） ions onto the biomass. Obviously, the adsorption equilibrium data for the two ions were reasonably described by typical Langmuir isotherm.     

Di（2-ethylhexyl）phosphoric acid-coconut oil supported liquid membrane for the separation of copper ions from copper plating wastewater

Permeation of Cu(II) from its aqueous solution through a supported liquid membrane (SLM) containing di(2-ethylhexyl)phosphoric acid (D2EHPA) carrier dissolved in coconut oil has been studied. The effects of Cu(II), pH (in feed), H2SO4 (stripping) and D2EHPA (in membrane) concentrations have been investigated. The stability of the D2EHPA-coconutoil has also been evaluated. High Cu(II) concentration in the feed leads to an increase in flux from 4.1 × 10-9 to 8.9 × 10-9 mol/(m2·s) within the Cu(II) concentration range 7.8×10-4-78.6×10-4 mol/L at pH of 4.0 in the feed and 12.4 × 10-4 mol/L D2EHPA in the membrane phase. Increase in H2SO4 concentration in strip solution leads to an increase in copper ions flux up to 0.25 mol/L H2SO4, providing a maximum flux of 7.4 × 10-9 mol/(m2·s). The optimum conditions for Cu(II) transport are, pH of feed 4.0, 0.25 mol/L H2SO4 in strip phase and 12.4 × 10-4 mol/L D2EHPA (membrane) in 0.5 (m pore size polytetrafluoroethylene (PTFE) membrane. It has been observed that Cu(II) flux across the membrane tends to increase with the concentration of copper ions. Application of the method developed to copper plating bath rinse solutions has been found to be successful in the recovery of Cu(II). rane. It     

Elemental Contamination of Rainwater by Airborne Dust in Tamale Township Area of the Northern Region of Ghana

Rainwater samples were collected from Tamale town in the 1997 and 1998 rainy seasons. During this period road construction in the Tamale area resulted in the generation of suspended dust in the atmosphere. Analysis of the samples for major ions showed elevated levels of Cl^–. Ion ratios with Cl^– (Na⁺/Cl^–, K⁺/Cl^–, Ca²⁺/Cl^–/Cl^– Mg²⁺/Cl^– and SO₄ ^2–/Cl^–) in rainwater samples were higher than the corresponding ratios in seawater. Some samples also showed elevated concentrations of Fe, Mn, Al and Zn, all of which except Zn showed a correlation with the dry periods between rainfall events. Consequently, it was concluded that dust generated from lateritic soils was probably the major cause of the increase in concentration of these metals. Aluminium and Fe concentrations were observed to be higher than the World Health Organization drinking water guide limits.     

可变电荷土壤和恒电荷土壤Cl-吸附特性的研究

对不同浓度KCl和不同pH下,3种可变电荷土壤和4种恒电荷土壤Cl-吸附量进行了测定。结果表明,土壤Cl-吸附量随平衡Cl-浓度C（e）增加而增大,恒电荷土壤呈线性,可变电荷土壤在添加Cl-0.5~5.0mmol/L下,符合Langmuir吸附等温式。同一浓度下的Cl-吸附量及其随浓度增加的速率均为砖红壤>红壤>赤红壤>黄棕壤>棕壤、暗棕壤和黑土,与这些土壤所带正电荷量顺序相一致。Langmuir方程K值较小且几种土壤差异不大。恒电荷土壤对Cl-的吸附量很小,在浓度较低时常出现负吸附,其吸附机理可能更多的是与K+吸附时的同时吸附。7种土壤Cl-吸附量均随pH增加而降低,但降低强度可变电荷土壤远大于恒电荷土壤。     

重金属离子的生物吸附容量与离子性质之间的关系

利用金属离子毒性评价和预测领域中的QSAR方法,探讨了重金属离子性质对生物吸附容量的影响．选用啤酒工业废弃的酿酒酵母为生物吸附剂,进行了10种金属离子Ag^＋,Cs^＋,Zn^＋,Pb^2＋,Ni^2＋,Cu^2＋,CO^2＋,Sr^2＋,Cd^2＋,Cr^3＋的生物吸附实验．选用22种参数来表征金属离子的物理化学性质,建立了金属的离子特性与生物吸附容量之间的关系．利用Langmuir方程计算得到酵母吸附金属离子的理论最大吸附量qmax,由大到小排序为Pb^2＋〉Ag^＋〉Cr^3＋〉Cu^2＋〉Zn^2＋〉Cd^2＋〉Co^2＋〉Sr^2＋〉Ni^2＋〉Cs^＋．离子性质与吸附量之间的线性拟合分析结果表明,共价指数Xm^2r与qmax具有良好的线性关系,共价指数越高,离子吸附量越大,金属离子与吸附剂表面官能团共价结合所占比重越大,键结合越牢固．对金属离子进行分类（按价态或离子的软硬性质）可以改善拟合效果．极化力Z^2／r、水解常数｜lgKOH｜、电离势,尸等多种物化性质与不含软离子的离子之间的理论最大吸附量也表现出良好的线性关系．     

JYZ0315菌吸附水体中Cr(Ⅵ)Cd(Ⅱ)共存重金属离子

采用JYZ0315菌种进行水体中Cr(Ⅵ)、Cd(Ⅱ)去除实验研究,结果表明:JYZ0315菌吸附水中Cr(Ⅵ)、Cd(Ⅱ)效果显著。吸附C(rⅥ)的最佳条件是:pH 3、1h、10℃,菌体的吸附容量为8.51mg/g;吸附Cd(Ⅱ)的最佳条件是:pH 5、30min、30℃,菌体的吸附容量为11.99mg/g。     

大分子络合超滤技术去除溶液中镍离子的研究

采用聚丙烯酸(PAA)和羧甲基纤维素钠(CMC)去除Ni2 ,首先将Ni2 离子络合在大分子上形成大分子络合物,进而通过超滤膜,将其截留在膜的一侧,从而达到分离镍离子的目的.研究表明,采用这两种聚合物进行络合超滤可以使镍离子去除率达到95%以上;当Ni2 与聚合物的反应时间为30 min时,镍离子(170 mg/L)与PAA(0.5 wt%)、CMC(0.5wt%)的适宜配比分别为1:2.5和1:1.在分离体系中加入Na 、Mg2 后,对镍离子的去除具有不利影响.此外,考察了用大分子络合超滤法处理含有镍离子的实际废水,结果在透过液中未检测出Ni2 .     

金属离子对有机垃圾两相厌氧系统中UASB处理效果的促进作用

在"水解溶出 UASB反应器"处理城镇有机垃圾的两相厌氧系统中,向UASB反应器进水中添加K、Mg、Fe、Co、Ni 5种金属离子的组合促进剂,通过对UASB反应器容积负荷、产气量、产甲烷量在添加组合促进剂前后的比较,研究了组合促进剂(K、Mg、Fe、Co、Ni)对有机垃圾浸出液厌氧消化过程的促进作用.试验结果表明,添加组合促进剂后,反应器的平均容积负荷从12.89 kg COD/m3·d提高到17.79 kg COD/m3·d;平均污泥负荷从0.82 kg COD/kg VSS·d提高到1.07 kg COD/kg VSS·d.此外,平均每千克COD产气量为392.5 L,比添加组合促进剂之前增大了6.4%;而平均每千克COD产甲烷量为297.5 L,比添加组合促进剂之前增大了10.5%.对于氨氮、挥发性脂肪酸(VFA)、pH及碱度来说,在添加组合促进剂之后则无大的变化.