Biosorption of chromium(VI), nickel(II) and copper(II) ions from aqueous solutions using Pithophora algae

The biosorption of heavy metals is considered to be one of the best alternatives for the treatment of wastewater. The metal binding capacity of algae and acid-treated algae is investigated to find out the removal characteristics of Cr(VI), Ni(II) and Cu(II) ions from single metal solutions. Batch experiments are conducted and the study is extended to investigate the effect of pH, amount of adsorbent and adsorbate concentration on the extent of biosorption. The results indicate that the adsorption capacity of algae depends strongly on pH. The maximum adsorption of Cr(VI), Ni(II) and Cu(II) occurs at pH values of 2, 7 and 4.3, respectively. The adsorption process follows first-order kinetic equation. The data obtained are correlated with Freundlich and Langmuir adsorption isotherms.     

新千年的能源

本文讨论了有关能源的思想观念的演变.20年前当几位作者开始携手合作研究能源时,人们一般是以发展的眼光、从供应方的角度来考虑能源问题,将注意力集中到消费趋势以及如何扩大供给以满足不断增长的需求上.这种方法在能源利用的环境影响、安全性和公平合理性方面的研究局限深深地困扰着他们.例如,大约有20亿人口经济条件有限,买不起现代能源,这严重限制了他们生活水平的提高.此外,能源还是造成环境问题的重要因素,其中包括室内空气污染、城市空气污染、酸化和全球气候变暧等.笔者认为,应当树立新的能源供给观念,使能源的供给方式有助于解决这些严重问题.笔者主张,能源必须成为推进可持续发展——经济上可行、以需要为导向、自力更生的能及无损于环境的发展——的工具,而且,应当将研究重点放在能源的终端用途上和能源供应的服务上.有助于实现可持续发展目标的能源技术方案也在本文进行了讨论.文中强调了制订和运用新型能源技术解决方案的必要性.笔者以巴西乙醇的利用为例,阐述了使发展中国家避免重复工业化国家所犯错误而在技术上实现跨越式发展的可能性.文中还重点介绍了在发展中国家引进先进技术过程中外国直接投资可能起到的作用,阐述了农村能源的近期和远期战略.最后,介绍了促进能源系统的发展,使之与可持续发展的步调一致并且支持可持续发展的相关政策.     

HIV sero-prevalance in general population of Warangal, A.P., South India

HIV/AIDS pandemic has devastated many countries reversing national development; HIV was not seen in Asia and India till 1980. Now India has become epicenter of AIDS pandemic. During April 2002 to March 2003 the HIV+ ve pregnant women and their husbands were encouraged to enroll in the prospective study with informed consent. The study results consist of most of the females who are in the age group between 16-25 years who were affected by HIV High infection is observed in people with lower socio-economic and education background. High infection rate is observed in house wives (26.7%), laborers (23%) and agricultural workers (12.1%) followed by toddy tapers (5%), drivers (5.96%) and others (6 47%). HIV +ve subjects at Mother To Child Transmission (MTCT) centers are surprisingly clinically very healthy. No disease manifestation was noticed.     

Study on Synthesis of Comb-Shaped Chitosan-Graft-Polyethylenimine Dithiocarbamate Material and Its Adsorption to Heavy Metal Ions

Journal of Polymers and the Environment - How to efficiently and economically remove heavy metals from sewage has been a huge challenge in the world. This article reports on an adsorbing material...     

Effect of decontamination and processing on insecticide residues in grape (Muscat Hamburg)

Environmental Science and Pollution Research - Field and laboratory experiments were conducted to study the effect of simple decontamination methods and processing on imidacloprid, dimethoate, and...     

Energy poverty and economic development: evidence from BRICS economies

Environmental Science and Pollution Research - In the development concern, all countries are started increasing production of energy across the world. All countries have started expansion of access...