Biosorbents based on pine sawdust and malt sprouts for preconcentration and ICP-OES determination of nonferrous,heavy, and precious metals in the environmental samples

Pine sawdust and malt sprouts modified with orthophosphoric acid and carbamide have been proposed for solid-phase extraction (SPE) of nonferrous, heavy, and precious metals and their subsequent determination in the environmental samples by inductively coupled plasma optical emission spectrometry (ICP-OES). Modified adsorbents were characterized by SEM, TGA, and FT-IR and compared with native matrixes. SPE of some nonferrous and precious metal ions by biosorbents was studied. Depending on the SPE conditions, it was possible to separate nonferrous and heavy metals from alkali and alkaline earth metals. The proposed adsorbents are effective for preconcentration of nonferrous and heavy metals from natural waters and precious metals from solutions after digestion of geological samples.     

Biosorption of chromium (VI) from aqueous solution by seed powder of prickly pear (Opuntia ficus indica L.) fruits

ABSTRACT

The solid residue of the cold press oil extraction from prickly pear (Opuntia ficus indica L.) fruit seeds was evaluated as a low-cost biosorbent for biosorption of Cr(VI) from aqueous solutions. Batch experiments were conducted as a function of initial pH, contact time, biosorbent dose, initial Cr(VI) concentration, and temperature. Biosorption was highly pH-dependent and found to be maximum at pH 1.0. Langmuir and Freundlich equations fitted very well with experimental data. The maximum monolayer adsorption capacity was 19.61 mg/g at 298 K and pH 1.0. Biosorption kinetics was controlled by the pseudo-second-order model. Thermodynamic parameters indicated that biosorption of Cr(VI) was a spontaneous, favorable and endothermic process. The activation energy was found to be 40.68 kJ.mol^?1.     

溶液中其他离子对微生物吸附铀的影响

讨论了溶液中存在的其他离子对微生物吸附铀的影响。研究结果表明，溶液中共存的Fe^3 、Fe^2 、Al^3 、Pb^2 、Cu^2 、Zn^3 、Cr^3 等阳离子抑制了微生物对铀的吸附能力，使吸附能力降低了25％～85％，影响十分显著。SO4^2-对铀的吸附影响较小。     

啤酒酵母菌固定化凝胶颗粒吸附铀的研究

啤酒酵母菌对铀有较大的吸附能力,为了增加其在实际应用中的稳定性,对用甲醛交联,海藻酸钙包埋固定的这种细菌吸附铀进行了初步的研究。结果表明,啤酒酵母菌经甲醛交联后,每g最大理论铀吸附量达185 2mg,海藻酸钙包埋固定后,每g最大理论铀吸附量达769 2mg,固定化后为其今后的工业应用奠定了基础。     

生物吸附及含铀废水生物处理技术简介

介绍了微生物及产物固定金属的方法、原理及含铀废水的生物处理方法。简单探讨了用生物法对地浸地下水的复原。     

微生物选矿剂研究进展

随着人们环保意识的提高,对于选矿绿色环保发展的呼声日益强烈,传统选矿药剂无论是从来源的有限性、对环境的污染性还是从浮选效率方面,都难以满足要求。而微生物选矿剂因来源广泛、无毒、选择性好等优点,近年来得到越来越多的重视,并期望将其工业化以替代或部分替代化学药剂。本文结合国内外相关研究结果,概述了微生物在矿物絮凝剂、矿物浮选剂及微生物的代谢产物作为选矿剂等方面的应用研究进展,并对微生物选矿剂的作用机理及其发展趋势进行了总结与展望。     

铬污染的微生物吸附技术研究进展

近年来,铬在工业生产中得到了广泛的应用,随之而来的含铬污染物对周围环境造成严重的污染和破坏,铬污染的修复已成为亟待解决的环境问题。微生物在铬污染的生物修复中发挥着重要的作用。它因铬污染修复过程中环保有效,安全可靠且无二次污染等优点,引起了相关学者们的广泛关注。首先简述了铬污染危害及传统处理技术,重点综述了微生物作为生物吸附剂的吸附机理及影响因素,并分别详述了典型细菌,真菌,酵母和藻类吸附Cr(VI)污染物的机理机制及相关研究进展,然后总结了微生物吸附Cr(VI)过程中铬浓度,赋存状态,微生物营养类型,培养条件及代谢产物等的主要影响因素,最后,分析了以微生物作为生物吸附剂所存在的问题并展望了未来的研究方向,结合基因工程和酶工程选育高效工程菌、开展多种技术联合应用等方法提高微生物对铬污染的去除能力。     

Continuous-flow metal biosorption in a regenerable Sargassum column

Metal biosorption behavior of raw seaweed S. filipendula in ten consecutive sorption-desorption cycles has been investigated in a packed-bed flow-through column during a continuous removal of copper from a 35mg/L aqueous solution at pH 5. The elutant used was a 1% (w/v) CaCl2/HCl-solution at pH 3. The sorption and desorption was carried out for an average of 85 and 15h, respectively, representing more than 41 days of continuous use of the biosorbent. The weight loss of biomass after this time was 21.6%. The Cu-biosorption capacity of the biomass, based on the initial dry weight, remained relatively constant at approximately 38 mg Cu/g. Loss of sorption performance was indicated by a shortening breakthrough time and a broadening mass-transfer zone. The column service time, considered up to 1 mg Cu/L in the effluent, decreased continuously from 25.4 h for the first to 12.7 h for the last cycle. The critical bed length, representing the mass-transfer zone, increased almost linearly from 28 to 34cm. "Life-factors" for S. filipendula were found to be 0.0008h(-1) for the breakthrough time and 0.008cm/h for the critical bed length, using an exponential decay and linear fitting functions, respectively. Regeneration with CaCl2/HCl at pH 3 provided elution efficiencies up to 100%. Maximum concentration factors were determined to be in the range 16-44, a decreasing tendency was observed with an increasing exposure time.     

重金属废水处理方法研究进展

随着我国经济的快速发展,工业废水大量排放,使得水体重金属污染日益严重,而重金属同时又是重要的资源,如何将其从水体中分离回收,是当前环境保护领域研究的热点之一。目前,水体重金属污染的处理方法主要有化学法、物理法和生物法。本文综述了近年来重金属废水处理方法的研究进展,并对该类研究进行了展望。