硫脲用量对菠菜生理指标及土壤氮素转化的影响

采用盆栽法,研究了硫脲不同用量(0%、1%、3%、5%、7%)对菠菜生长、硝酸盐累积、土壤氮含量及叶绿体色素含量的影响.结果表明,不同硫脲用量对菠菜的单盆重、株高均有提高.随硫脲用量的增加,菠菜叶绿体色素含量均有提高;硫脲能显著降低菠菜硝酸盐含量,随着硫脲用量的增加,降低效果提高,其中硫脲用量为7%时,降低效果达极显著水平.硫脲对土壤硝态氮累积的抑制作用随硫脲用量的增加而增强,硫脲用量达7%时,抑制作用表现为极显著.     

生物滴滤器中水分对憎水性气态污染物净化性能的影响

通过改变稳定工况下的液气比和测定风干过程中滴滤床净化和阻力性能变化,研究了水分对气体生物滴滤器(BTF)净化甲苯性能的影响,结果表明,生物滴滤器净化憎水性挥发性有机物的性能受滤床水分影响较大,与通常气液吸收过程不同,憎水性气体挥发性有机物的生物滴滤过程存在达到最佳净化效果的液气比,风干过程实验表明,滴滤器中水分含量太高,会影响憎水性污染物和氧气等在气相与生物相之间的传质过程;但水分太低又会影响滴滤器内生物相的活性,对生物滴滤器净化憎水性挥发性有机物而言,存在最适滤床水分,可通过监测设备压降来控制滴滤塔内水分。     

用累托石吸附处理含铁(Ⅲ)废水

用累托石作吸附剂处理有色金属厂冶炼过程中产生的含Fe(Ⅲ)废水。在废水pH为7．5～8．5、反应时间为30min、累托石投加量为12g／L的条件下,Fe(Ⅲ)质量浓度可由5mg／t．降到0．08mg／L,Fe(Ⅲ)的去除率最高为98．4％,外排废水符合GB8978--1996一级标准。对Fe(Ⅲ)进行等温吸附实验,其等温吸附曲线符合Langmuir模型,其吸附机理主要是吸附作用和沉淀作用。     

废水催化湿式氧化稀土金属氧化物催化剂的研制

采用共沉淀法制得锰铈复合氧化物催化剂,催化湿式氧化处理高浓度苯酚废水。通过正交实验筛选催化剂制备条件,单因素实验优化制得催化剂。研究了CWAO处理废水条件下的金属离子溶出和催化剂的表征。结果表明,该催化剂在低温低压条件下具有优良的湿式氧化催化活性,且金属离子溶出量低,是一种CWAO处理高浓度有机废水中极具应用前景的新型高效催化剂。     

硫酸锰废渣浸出毒性及淋溶特性研究

长沙市兴镇13家硫酸锰厂的生产废渣使当地的生态环境造受到了严重破坏。本文在废渣浸出毒性实验、渣柱淋滤实验以及废渣的全分析基础上,全面地研究了废渣的组成、浸出毒性大小以及在当地酸沉降条件下的淋滤特征,为其安全处置提供了理论基础。研究证明,废渣中重金属种类多、含量高,尤其是锰,高达138800mg/kg。渣的浸出毒性虽未达到国家规定的危险废物鉴别标准,但远超过了《污水综合排放标准》,其衰减可用负指数方程来描述。在酸雨淋溶下,渣中的锰离子会在短时期内大量释放后,维持在一相对较低水平长期释放,对环境威胁巨大。     

厌氧折流板反应器处理生活污水的运行特性

以厌氧消化污泥作为厌氧折流板反应器ABR的接种污泥,研究恒温(35℃)条件下ABR处理生活污水的启动和运行特性。实验结果表明,ABR反应器仅用了39 d就完成初次启动,COD去除率一直稳定在60%左右。在以后运行的5个阶段里,即当水力停留时间为4~10 h,容积负荷为1.17~2.9 kg COD/m3.d,反应器对COD的平均去除率基本稳定在70.49%~80.2%;并且当HRT=7 h,VRL=1.612 kg COD/m3.d时,反应器对COD的去除率平均高达80.2%,平均COD出水低于100 mg/L。在实验过程中(除启动阶段外),反应器出水碱度均远远大于进水碱度,VFA均在1.5 mmol/L以下。     

双齿许水蚤(Pseudodiaptomus dubia)对亚热带虾池Cu和Zn的富集

重金属污染是对虾养殖环境主要污染现象之一,查明重金属在环境中的迁移规律对养殖水质调控和对虾健康养殖具有重要意义.本文采用火焰原子吸收分光光度计测定在不同暴露时间下双齿许水蚤(Pseudodiaptomusdubia)对Cu和Zn的富集量,研究了双齿许水蚤对Cu和Zn富集动力学,并探讨了温度和盐度对其富集的影响.结果表明:双齿许水蚤对Cu和Zn的富集过程均经历了快速、慢速和平衡3个阶段,实验24h达到富集平衡;双齿许水蚤对Cu和Zn的富集动力学参数k1(Cu)=0.077＜k1(zn)=0272,BCF(cu)=0.344＜BCFZn)=2.252,双齿许水蚤对Zn的富集速率和富集能力均大于Cu.温度对双齿许水蚤Cu和Zn富集的影响显著(p＜0.05),最适温度范围为15 ～30℃;盐度对双齿许水蚤Zn富集的影响极显著(p＜0.01),而对Cu富集的影响不显著(p＞0.05),对Cu和Zn适宜的富集盐度范围为10 ～35.这些研究结果说明,双齿许水蚤对Cu和Zn均具有较强的富集能力,在对虾养殖期间,应通过循环过滤设施去除受到重金属污染池塘中的浮游动物,减少幼虾对其摄食和虾体中重金属的积累量,从而降低食品安全隐患.     

Remediation of soil and groundwater contaminated with organic chemicals using stabilized nanoparticles: Lessons from the past two decades

▪ Overviewed evolution and environmental applications of stabilized nanoparticles. ▪ Reviewed theories on particle stabilization for enhanced reactivity/deliverability. ▪ Examined various in situ remediation technologies based on stabilized nanoparticles. ▪ Summarized knowledge on transport of stabilized nanoparticles in porous media. ▪ Identified key knowledge gaps and future research needs on stabilized nanoparticles. Due to improved soil deliverability and high reactivity, stabilized nanoparticles have been studied for nearly two decades for in situ remediation of soil and groundwater contaminated with organic pollutants. While large amounts of bench- and field-scale experimental data have demonstrated the potential of the innovative technology, extensive research results have also unveiled various merits and constraints associated different soil characteristics, types of nanoparticles and particle stabilization techniques. Overall, this work aims to critically overview the fundamental principles on particle stabilization, and the evolution and some recent developments of stabilized nanoparticles for degradation of organic contaminants in soil and groundwater. The specific objectives are to: 1) overview fundamental mechanisms in nanoparticle stabilization; 2) summarize key applications of stabilized nanoparticles for in situ remediation of soil and groundwater contaminated by legacy and emerging organic chemicals; 3) update the latest knowledge on the transport and fate of stabilized nanoparticles; 4) examine the merits and constraints of stabilized nanoparticles in environmental remediation applications; and 5) identify the knowledge gaps and future research needs pertaining to stabilized nanoparticles for remediation of contaminated soil and groundwater. Per instructions of this invited special issue, this review is focused on contributions from our group (one of the pioneers in the subject field), which, however, is supplemented by important relevant works by others. The knowledge gained is expected to further advance the science and technology in the environmental applications of stabilized nanoparticles.