Immobilization of Pb(II), Cd(II) and Ni(II) ions on kaolinite and montmorillonite surfaces from aqueous medium

The present study investigates the immobilization of Pb(II), Cd(II) and Ni(II) on clays (kaolinite and montmorillonite) in aqueous medium through the process of adsorption under a set of variables (concentration of metal ion, amount of clay, pH, time and temperature of interaction). Increasing pH favours the removal of metal ions till they are precipitated as the insoluble hydroxides. The uptake is rapid with maximum adsorption being observed within 180 min for Pb(II) and Ni(II) and 240 min for Cd(II). A number of available models like the Lagergren pseudo first-order kinetics, second-order kinetics, Elovich equation, liquid film diffusion and intra-particle diffusion are utilized to evaluate the kinetics and the mechanism of the immobilization interactions. Two isotherm equations due to Langmuir and Freundlich showed good fits with the experimental data. Kaolinite and montmorillonite have considerable Langmuir monolayer capacity with respect to Pb(II), Cd(II) and Ni(II), the values being in the range of 6.8-11.5mg/g (kaolinite) and 21.1-31.1mg/g (montmorillonite). The Freundlich adsorption capacity follows a similar order. The thermodynamics of the immobilization process indicates the same to be exothermic with Pb(II) and Ni(II), but endothermic with Cd(II). The interactions with Pb(II) and Ni(II) are accompanied by decrease in entropy and Gibbs energy while the endothermic immobilization of Cd(II) is supported by an increase in entropy and an appreciable decrease in Gibbs energy. The results have established good potentiality for kaolinite and montmorillonite to remove heavy metals like Pb(II), Cd(II) and Ni(II) from aqueous medium through adsorption-mediated immobilization.     

泉州市移动通信基站电磁辐射环境影响分析

对泉州市移动通信GSM基站和TD—SCDMA基站电磁辐射状况进行监测与分析。通过理论计算预测基站电磁辐射安全距离,对典型敏感目标、典型基站进行电磁辐射的监测,结果与理论预测情况相符。选取302个GSM基站和306个TD—SCDMA基站进行电磁辐射的监测,结果表明,各基站电磁辐射满足单个项目管理低于目标限值0．08W／m2的标准。分析表明,基站在正常运行时,对周围的电磁辐射环境影响能满足国家相应标准的要求。     

As（V）在金红石TiO2颗粒表面吸附特性及机理

通过静态动力学和热力学吸附实验,研究了温度、共存离子以及溶质的初始浓度对As（V）在金红石TiO2颗粒表面吸附的影响,探讨了As（V）在金红石TiO2颗粒表面吸附特性及机理。结果表明,在As（V）初始浓度为10mg／L,pH为7的条件下,25℃时的吸附量0．41mg／g高于30℃时的吸附量0．31mg／g,As（V）在金红石TiO,上的吸附为放热过程。CaCl2和MgCl2的添加对As（V）在金红石TiO2表面吸附起到明显的促进作用。T=25℃,Ca2＋或Mg2＋浓度为10mmol／L时,As（V）吸附量分别为0．64和0．56mg／g,Ca2＋比Mg2＋对As（V）吸附促进作用强。As（V）在金红石TiO2的吸附等温线符合Frendlich方程,Lagergren二级动力学方程能较好地描述As（V）在金红石TiO2颗粒表面吸附的动力学过程。     

磷酸活化-微波热解改性污泥对镉的吸附性能

以城市污水处理厂剩余污泥为原料,利用磷酸活化-微波热解制取改性污泥。以此污泥作为吸附剂,对含Cd2+废水进行了吸附实验研究。考察了溶液反应时间、Cd2+浓度、pH值和吸附剂用量对镉吸附去除效果的影响;利用等温吸附实验作出吸附等温线,并考察了改性污泥吸附剂吸附Cd2+的动力学方程。实验结果表明,改性污泥对Cd2+有良好的吸附性能,吸附最佳pH值为6.0,吸附较好地符合一级动力学吸附模型和Langmuir-Freundlich等温吸附方程,吸附为物理吸附,吸附反应发生12 h后达到吸附平衡。     

黑龙江省东部煤电化基地经济与生态环境协调发展评价研究

构建东部煤电化基地是继哈大齐工业走廊启动建设后,黑龙江省做出的一项重大战略部署。基地建设要求深入贯彻科学发展观,大力发展煤化工产业,实现全面、协调、可持续发展。全面协调发展不仅是经济的发展,同时也要考虑生态环境的保护。运用层次分析法和协调发展度模型,研究黑龙江东部煤电化基地经济和生态环境的协调发展程度表明,黑龙江东部煤电化基地经济和生态环境协调发展水平处于中等协调状况。针对评价结果,提出了相应的对策和建议。     

Enhanced resistance of yeast mutants deficient in low-affinity iron and zinc transporters to stannous-induced toxicity

Tin or stannous (Sn²⁺) compounds are used as catalysts, stabilizers in plastic industries, wood preservatives, agricultural biocides and nuclear medicine. In order to verify the Sn²⁺ up-take and toxicity in yeast cells we utilized a multi-elemental analysis known as particle-induced X-ray emission (PIXE) along with cell survival assays and quantitative real-time PCR. The detection of Sn²⁺ by PIXE was possible only in yeast cells in stationary phase of growth (STAT cells) that survive at 25 mM Sn²⁺ concentration. Yeast cells in exponential phase of growth (LOG cells) tolerate only micro-molar Sn²⁺ concentrations that result in intracellular concentration below of the method detection limit. Our PIXE analysis showed that STAT XV185-14c yeast cells demonstrate a significant loss of intracellular elements such as Mg, Zn, S, Fe and an increase in P levels after 1 h exposure to SnCl₂. The survival assay showed enhanced tolerance of LOG yeast cells lacking the low-affinity iron and zinc transporters to stannous treatment, suggesting the possible involvement in Sn²⁺ uptake. Moreover, our qRT-PCR data showed that Sn²⁺ treatment could generate reactive oxygen species as it induces activation of many stress-response genes, including SOD1, YAP1, and APN1.     

百色市右江区大气PM10中水溶性无机离子的化学特征与来源

2010年10月至2011年9月采集百色市右江区大气PM10样品,分析PM10及其水溶性无机离子的化学特征与来源。结果表明:(1)百色市右江区大气PM10为13.89～319.44μg/m3,年均117.48μg/m3,年均值超过《环境空气质量标准》(GB 3095-2012)二级标准(100μg/m3)。百色市右江区大气可吸入颗粒物的污染主要出现在春冬季节。(2)水溶性无机离子浓度年均值依次为SO24->NO3->Cl->NH4+>K+>Na+>Mg2+>F-,SO24-、NO3-和Cl-浓度最高,分别占水溶性无机离子的57.7%、14.9%和14.5%。(3)百色市右江区大气PM10呈较强的酸性,高浓度的SO42-可能是导致百色市右江区大气PM10呈较强酸性的主要原因。(4)PM10的季节变化受气温和风速的影响极显著;气象因素对SO42-、NO3-、F-的影响不显著。(5)主因子分析表明,PM10中水溶性无机离子可能来自3个方面,Cl-和NO3-主要来自于当地低烟卤煤燃烧排放的烟气;Mg2+、K+和Na+主要来自于自然源;F-、SO24-和NH4+主要来自于混合源。     

改性多壁碳纳米管对水中Cd~（2＋）的去除

为了增加多壁碳纳米管（multiwall carbon nanotubers,MWNTs）对水中Cd2＋的吸附量,使用混酸对多壁碳纳米管进行氧化处理,采用红外光谱进行结果表征,并探讨了吸附时间、pH值和MWNTs的使用量、Cd2＋的浓度及干扰离子对镉离子吸附的影响。结果表明,吸附时间为1.5 h、pH为5.3、吸附效果最佳,随MWNTs量的增加Cd2＋去除量增加,共存的阳离子会降低对Cd2＋的吸附效果,对Cd2＋的吸附符合Longmuir吸附定律。研究同时表明,pH小于2时Cd2＋能容易从碳纳米管上解吸。初步探讨了Cd2＋吸附机制。     

江苏沿海风能资源禀赋与开发利用研究

江苏沿海地区拥有丰富的风能资源,开发前景十分广阔,尤其是中部、南部地区拥有广阔的沿海滩涂和辐射沙洲,建设沿海风电场的条件优越,是打造江苏"海上三峡"新能源基地的希望所在。阐述了江苏沿海风能资源开发的重要意义,分析了沿海风能资源的禀赋与时空分布特点,指出江苏沿海岸区风能资源丰富,且沿海滩涂宽广,是建立大型风力发电场的理想之地,在此基础上提出发展江苏沿海绿色能源基地的构想。     

TiO_2/EP光催化降解水体中微污染磺胺嘧啶的研究

制备了膨胀珍珠岩(EP)为载体的TiO2催化剂(TiO2/EP),对使用较为广泛的抗生素磺胺嘧啶(SDZ)进行了光催化降解研究,探讨了TiO2的负载量、溶液的初始浓度、初始pH、无机离子(HCO3-、SO42-和Cl-)和腐殖酸(HA)对SDZ降解效果的影响。结果表明:SDZ的光催化降解符合一级反应动力学方程;当TiO2最佳负载量为20 wt%,SDZ浓度为5 mg/L,pH=6.7,紫外光照射强度为1 000μW/cm2,反应时间为45 min时,SDZ的降解率达到96%;HCO3-在低浓度时能促进SDZ的光催化降解,高浓度时促进作用不明显;SO42-和Cl-对SDZ的光催化降解有轻微的抑制作用;HA对SDZ光催化降解有显著的抑制作用,浓度越高,抑制作用越强。UV-TiO2/EP是一种去除水体中微污染SDZ的有效方法。