不锈钢-铝电极电絮凝处理含铜废水的试验研究

采用不锈钢-铝为电极的电絮凝法对含铜废水进行了处理试验研究,模拟废水铜离子浓度为150 mg/L,以废水中的铜离子浓度和COD去除率为考察指标,在电流密度为15 mA/cm2、极板间距为3 cm、pH值为7、电解时间为120 min的条件下,Cu2+的去除率平均能达到99%以上,COD的去除率亦能达到97%;在此基础上,应用于实际的电路板腐蚀液废水的处理试验,发现Cl-浓度在200 mg/L以上时,对废水先进行相关预处理也能达到较好的处理效果,该研究对进一步探讨Cl-对电絮凝的影响机理有一定的借鉴意义。     

零价铁对脱色希瓦氏菌S12偶氮还原的促进作用

以脱色希瓦氏菌(Shewanella decolorationis)S12为实验菌株,研究了零价铁(ZVI)存在条件下微生物的厌氧偶氮还原特性及其最佳反应条件.结果表明,ZVI可显著促进菌株S12的厌氧偶氮还原速率.培养30 h后含有20 mmol.L-1微米级ZVI和S12菌的培养体系中,菌株S12对1 mmol.L-1苋菜红的脱色率达100%,比不含ZVI的S12菌培养体系和只含ZVI的体系的偶氮还原率分别提高了23.16%和94.66%;在额外含20 mmol.L-1甲酸钠的培养体系中,ZVI的存在也使S12菌对苋菜红的脱色率提高了20.54%.此外,ZVI的存在可显著提高培养体系对偶氮染料的耐受能力.在投加ZVI和菌株S12培养体系中,连续批量投加浓度为1 mmol.L-1的苋菜红可在276 h内实现11次有效脱色,而不含ZVI的S12菌培养体系中只能实现3次有效脱色.进一步的研究发现,ZVI与菌株S12协同培养体系的最适反应pH为9.0,最适ZVI投加量为60 mmol.L-1.与毫米级和纳米级ZVI颗粒相比,微米级ZVI颗粒具有更强的促进作用.本研究结果将为利用ZVI协同促进偶氮染料的生物治理效果提供科学参数.     

Arsenic and chromate removal from water by iron chips-Effects of anions

The purpose of this study is to estimate the removal efficiency of As and Cr (VI) by one kind of industrial waste — iron chips, as well as to estimate the effects of typical inorganic anions (sulfate, phosphate, and nitrate), and typical organic anions (citrate, oxalate, and humate) on As or Cr (VI) removal. The results showed that 98% of As (V) and 92% of As (III) could be removed from aqueous phase by the iron chips within 60 min. Compared with As species, Cr (VI) was removed much more rapidly and efficiently with 97% of Cr (VI) being removed within 25 min. The removal efficiency for arsenic was in the order: As (III) (sulfate), As (III) (nitrate) or As (III), As (III) (humate), As (III) (oxalate), As (III) (citrate), As (III) (phosphate), and for chromate was in the order: Cr (VI) (sulfate), Cr (VI) (phosphate) or Cr (VI) (nitrate) or Cr (VI) (oxalate), Cr (VI), Cr (VI) (citrate), Cr (VI) (humate). In all the treatments, pH level increased with time except for As (III), the removal of which was either without anions or in the presence of humate or nitrate.     

石英砂负载氧化铁的表征及其除锑吸附性能研究

通过SEM/EDAX以及Nova-1000表面分析仪对石英砂负载的氧化铁颗粒进行了表征,发现负载氧化铁的粒径为200 nm左右,其表面孔径及孔隙率分别为2×10-9～9×10-9m及0.11%,负载氧化铁的石英砂的比表面积为原砂的5倍.考察了石英砂负载氧化铁(IOCS)在不同的实验条件下(吸附时间,pH值,温度等)对水溶液中锑的去除效果,在pH为3～9范围内,其去除率均超过了98%.吸附动力学及吸附等温线实验数据分别符合二级反应动力学模型及Langmuir等温吸附模型.热动力学实验结果进一步表明:IOCS吸附锑的过程是自发的、吸热的化学吸附反应.     

零价铁还原降解2,4-二硝基甲苯研究

研究了零价铁对2，4-二硝基甲苯(2，4-DNT)的还原降解情况。实验结果表明，2,4-DNT的还原降解率与溶液初始pH值、初始浓度、溶解氧含量和铁粉投加量等因素有关。2，4-DNT在还原过程中先生成2-氨基-4-硝基甲苯(2A4NT)和4-氨基-2-硝基甲苯(4A2NT)，最后被还原成2，4-二氨基甲苯(2，4-DAT)。     

嗜水气单胞菌强化老化纳米零价铁去除水中Cr(VI)

基于老化对纳米零价铁（NZVI）去除水中Cr（VI）的不利影响,本研究考察了接种嗜水气单胞菌（Aeromonas hydrophila）强化老化NZVI对水中Cr（VI）的去除,并分析了溶解氧、温度、pH、Cr（VI）初始浓度对其去除Cr（VI）的影响,同时利用扫描电镜（SEM）、X射线光电子能谱（XPS）等分析了反应前后材料的形貌特征及Cr的价态变化.结果表明,接种嗜水气单胞菌能显著提高无氧条件下老化NZVI对Cr（VI）的去除效果,且在酸性条件和30~40 ℃条件下去除效果较好,可能是因为该条件下更有利于老化NZVI的腐蚀和微生物的生长,此外,Cr（VI）去除效率随Cr（VI）初始浓度升高而降低.在pH=6,温度为30 ℃,老化nZVI投加量为0.1 g·L^-1,Cr（VI）初始浓度为50 mg·L^-1的条件下反应24 h后,Cr（VI）的去除率可达到100%.XPS分析表明,反应后NZVI表面沉积的Cr主要以Cr（III）的形式存在,可能为Cr（OH）₃沉淀或Fe_xCr_1-x（OH）₃共沉淀物.动力学研究发现,Cr（VI）去除过程符合准二级动力学,去除机制为Cr（VI）的吸附、还原与共沉淀,其中以还原作用为主.     

改性生物炭负载纳米零价铁去除水体中头孢噻肟

抗生素对环境的危害已经引起了人们的广泛重视.本实验以改性生物炭(MB)为载体制备了负载纳米零价铁的功能生物炭(Fe/MB).以头孢噻肟(CFX)为目标抗生素,研究了该材料对头孢噻肟的降解特性及影响因素,并探讨了去除机理.实验结果表明,50 min内头孢噻肟的去除率为92%(Fe/MB用量为0.4 g·L~(-1),溶液p H=5.0,头孢噻肟浓度为20 mg·L~(-1),振荡速率为200 r·min~(-1),柠檬酸浓度为1.47 mmol·L~(-1)).头孢噻肟的去除过程存在改性生物炭的吸附和纳米零价铁还原降解的协同作用,数据符合伪二级反应动力学方程(R20.99).采用紫外可见光谱结合质谱分析了降解产物的结构并提出头孢噻肟的降解途径.     

Adsorption of Pb, Cd to Fe, Mn oxides in natural freshwater surface coatings developed in different seasons

Metal oxides( Fe, Mn oxides) in natural surface coatings(biofilms and associated minerals) are believed to play a significant role n the fate and transport of trace metal in aquatic environments. Seasonal variation of Fe, Mn oxides and organic materials in surface oatings, which were developed periodically on glass slides in Nanhu Lake, Jilin Province, China over the time frame of three seasons,was investigated in order to understand the influence of metal oxides on Pb and Cd adsorption to heterogeneous surface coating materials(biofilm). Pb and Cd adsorption was measured under controlled laboratory conditions( mineral salts solution with defined speciation, ionic trength 0.05 mol/L, 25~C and pH 6.0). The classical Langmuir adsorption isotherm was applied to estimate equilibrium coefficients of Pb nd Cd adsorption to the surface coatings. In general, components in the surface coatings varied greatly with seasons altering and btained higher concentrations in summer while the content of iron oxides always exceeded that of manganese oxides. Correlation nalyses between the maximum adsorption of Pb and Cd and components in the surface coatings developed periodically indicated that Pb hase association with Mn oxides and Cd phase association with Fe oxides as well as Mn oxides were statistically significant. Effect of Mn xides on Cd adsorption was confirmed in view of its higher content in the surface coatings. The importance of ferromanganese oxides for b and Cd adsorption to the natural surface coatings developed in different seasons was evidenced.     

FeS自养反硝化与厌氧氨氧化的耦合脱氮机制

微生物的功能多样性对元素价态的转换存在协同作用是自然界关键的生态调节策略,充分利用这种策略,实现不同微生物的功能组合,可以发展废水处理新工艺.本文以静态批次实验的含氮污染物作为研究对象,把Fe S投加量、NO_3~--N/NO_2~--N比值、厌氧氨氧化(ANAMMOX,AN)和自养反硝化(AD)生物量之比作为反应控制条件,讨论了AN与AD之间代谢产物互补的合作机制,提出了(AN+AD)_(TN→0)脱氮工艺的概念.研究发现过量的Fe S投加在保证AD过程的彻底性之外,并不显著影响AN菌的代谢活性;提高NO_2~--N在电子受体中的比例,会使微生物复合群落处于代谢底物竞争关系之中,对TN的去除产生负面影响; AN生物量的增加加深了复合群落的合作程度,当初始NH_4~+-N与NO_3~--N的化学计量比小于0. 85时,可以实现TN浓度趋零.结果表明,通过认识微生物之间的交互作用,寻求复杂微生物群落功能的规划或调控,可以设计出更加合理的废水处理工艺,达到低物耗投入条件下目标污染物的高效去除.     

两种新型涂铁改性砂的过滤性能及反冲洗条件研究

以两种新型涂铁改性石英砂(纳米氧化铁改性砂,Nano-OCS;氧化铁改性砂,IOCS)及普通石英砂(RQS)为研究对象,考察了两种新型改性砂对沉后水腐殖酸及浊度的直接过滤效果,对其反冲洗条件进行优化研究,并对3种滤料的过滤效果进行了比较.结果表明,1滤层厚度为45 cm时,最佳滤速为6 m·h-1;3种滤料对腐殖酸和浊度的直接过滤效果依次为:Nano-OCSIOCSRQS,其中两种涂铁砂对腐殖酸的去除率分别为71.70%和61.61%;2Nano-OCS和IOCS滤柱的反冲洗流程分4步,对应的流程及最佳操作条件为:首先,用0.5 mol·L-1NaOH的溶液浸泡,气冲强度13 L·s-1·m-2,气冲时间6 min;然后,用0.075 mol·L-1的NaOH溶液与空气同时反冲洗,NaOH溶液冲洗强度为8 L·s-1·m-2,气冲强度13 L·s-1·m-2,冲洗时间3 min;接着用0.015 mol·L-1的FeCl3溶液与空气同时反冲洗,FeCl3溶液冲洗强度为8 L·s-1·m-2,气冲强度13L·s-1·m-2,冲洗时间2 min;最后,用清水冲洗,冲洗强度8 L·s-1·m-2,冲洗时间4 min.两种涂铁砂反冲洗前后表面形态结构更加复杂、粗糙度增加,对腐殖酸去除率进一步提高.3当滤层厚度由45 cm增加到80 cm时,Nano-OCS对腐殖酸直接过滤的最高去除率由74.6%提高至80.3%,平均去除率由57.9%提高至68.5%.