Use of Sorbents of Hot-Contact Coal Carbonization in the Power Industry

The many years of experience in the use of sorbents of hot-contact coal carbonization in the power industry is used for substantiation of their prospects for solving problems of power and materials saving and improving the reliability and safety of operation of power equipment. Results of tests of sorbents in systems of water conditioning of thermal power plants, cleaning of return condensates, mazut- and oil-contaminated process wastewaters, makeup water in heat networks, and biosorption cleaning of sewerage are presented. The sorption methods of cleaning are shown to have many advantages, to save expensive ion-exchange resins and reagents, to decrease the cost of desalinated water, and to prolong the service of power equipment. Comparative data are presented for basic commercial kinds of activated carbon and HCCC sorbents (ABD). The technical characteristics of sorbents of hot-contact coal carbonization are shown to be at the level of commercial sorbents or be higher at a much lower cost (by a factor of 2.5 – 3). It is shown that the creation of several HCCC installations with an output of 25 – 30 thousand tons of sorbents a year at coal-fired power plants will solve many water-cleaning problems of the EÉS Rossii Co. (The United Power Systems of Russia) and make it a monopolistic producer of activated carbon in the Russian market.     

Removal of Brill Red 5B from an aqueous solution using Cicca acida biomass

The biosorption of Brill Red 5B from an aqueous solution, using Cicca acida plant's leaves was investigated in a batch system with the influence of pH (1–6), temperature (25–35°C) and initial dye concentration (10–100 mg/L). Maximum biosorption was observed at initial pH of 2.0, temperature of 30°C and at the initial dye concentration of 100 mg/L. Batch biosorption kinetic was studied using the pseudo first and pseudo‐second‐order rate equations. From the result, it was observed that pseudo‐second‐order rate expression fitted the experimental data well when compared to pseudo first order kinetic model. The intra‐particle diffusion coefficient (K_i) and effective diffusion coefficient (D_i) values obtained for the sorption of Brill Red 5B using C. acida plant's leaves were found to be increased with increase in initial dye concentration.     

Biosorption of Radionuclides by Fungal Biomass

Four kinds of bioreactor were evaluated for thorium removal by fungal biomass. Static-bed or stirred-bed bioreactors did not give satisfactory thorium removal probably because of poor mixing. An air-lift bioreactor removed approximately 90–95% of the thorium supplied over extended time periods and exhibited a well-defined breakthrough point after biosorbent saturation. The air-lift bioreactor promoted efficient circulation and effective contact between the thorium solution and the mycelial pellets. Of several fungal species tested, Rhizopus arrhizus and Aspergillus niger were the most effective biosorbents with loading capacities of 0.5 and 0.6 mmol g^?1 respectively (116 and 138 mg g^?1) at an inflow thorium concentration of 3 mmol dm^?3. The efficiency of thorium biosorption by A. niger was markedly reduced in the presence of other inorganic solutes while thorium biosorption by R. arrhizus was relatively unaffected. Air-lift bioreactors containing R. arrhizus biomass could effectively remove thorium from acidic solution (1 mol dm^?3 HNO₃) over a wide range of initial thorium concentrations (0.1–3 mmol dm^?3). The biotechnological application and significance of these results are discussed in the wider context of fungal biosorption of radionuclides.     

Biosorption of palladium and platinum by sulfate‐reducing bacteria

The biosorption capacities of palladium and platinum were studied in three different species of Desulfovibrio: Desulfovibrio desulfuricans, Desulfovibrio fructosivorans and Desulfovibrio vulgaris. The influence of several parameters such as pH, acidic background and competitor anions on biosorption equilibria and biosorption kinetics were evaluated. Differences were observed between the three strains of Desulfovibrio with respect to the optimum biosorption parameters of both metals, suggesting differences in the metal speciation–dependent sorption mechanisms involved. The most promising Pd and Pt biosorption results were obtained using D desulfuricans with rapid achievement of equilibrium (90% of total sorption was achieved in 5–15 min) and a maximum value of 190 mg g^?1 dry biomass and 90 mg g^?1 dry biomass for Pd and Pt accumulation respectively, at pH 3. Copyright © 2003 Society of Chemical Industry     

Remediation of Cd(II) Metal Ion from Aqueous Systems by Using Calcium Alginate Modified (CAM) Acacia saligna and Delbergia sisso Pods Composite Beads

The present investigation reports the possibility of using Acacia saligna and Delbergia sisso pods to remove Cd(II) from aquatic systems in the form of calcium alginate modified immobilized composite beads (CAM-ASPCB and CAM-DSPCB). Batch and fixed bed column studies were carried out under various process affecting parameters. Maximum metal removal efficiency of 92% by CAM-ASPCB and 85% by CAM-DSPCB was observed under optimized conditions. Pseudo-second-order kinetic model, intra-particle diffusion, and Freundlich isotherm were found fitted well. The regeneration of the sorbents were found effectively high showing up to 10 cycles for simulated solution and up to 3 cycles for industrial effluent.     

A Comparative Study on the Biosorption of Cd2+ onto Paecilomyces lilacinus XLA and Mucoromycote sp. XLC

The filamentous fungi XLA and XLC isolated from Cd-contaminated soil were identified morphologically and phylogenetically as Paecilomyces lilacinus and Mucoromycote sp., respectively. The minimum inhibitory concentrations (MICs) of Cd²⁺, Co²⁺, Cu²⁺, Zn²⁺, Cr³⁺ and Cr⁶⁺ in minimum mineral (MM) medium agar plates were 29,786, 2945, 9425, 5080, 1785 and 204 mg·L⁻¹ for XLA and 11,240, 884, 9100, 2540, 3060 and 51 mg·L⁻¹ for XLC, respectively. Favorable biosorption conditions for adsorption of Cd²⁺ by the tested fungi were investigated. Efficient performances of the biosorbents were described using Langmuir isotherm model, and the predicted maximum biosorption capacities for Cd²⁺ were 77.61 mg·g⁻¹ of XLA and 79.67 mg·g⁻¹of XLC. Experiments on desorption potential of biosorbents validated their efficacy at a large scale. Results showed that XLA obtained a desorption rate of 84.7% by 2% EDTA and XLC gained a desorption rate of 78.9% by 0.1 M HCl. Analysis by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) and X-ray photoelectron spectroscopy (XPS) suggested that groups of C–N, COO– for XLA and C–N, CH₂ and phosphate for XLC were the dominant binding sites for Cd²⁺ biosorption. Our results indicated that the fungus XLA, rather than XLC, could potentially be used as an inexpensive, eco-friendly and effective bioremediation agent for the removal of Cd²⁺ from wastewater.     

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。     

啤酒酵母在处理含镉工业废水中的应用研究

研究了啤酒酵母对废水中镉离子的生物吸附过程，分析了啤酒酵母吸附镉离子的速度、pH、温度等的影响。实验表明，啤酒酵母对镉离子的吸附时间短（15min）；pH值范围宽（4～8）；酵母的单位吸附量大（46．5mg／g）。对于高浓度的含镉废水，酵母具有较强的吸附能力；废水经二次吸附处理后均能达到排放标准。用啤酒废酵母作为重金属离子的吸附剂，可提高啤酒企业的附加值和科技含量，也可降低啤酒企业排放废水时对环境的污染。（孙悟）     

偕胺肟基改性满江红干粉对水中U(VI)的吸附

采集池塘中的野生满江红制成满江红干粉后,经偕胺肟基改性,合成了偕胺肟基满江红干粉（AI-g-AO）。通过扫描电子显微镜、红外光谱、X射线光电子能谱表征分别表征了吸附前、后的AI-g-AO的微观组织结构。单因素实验用于研究pH、反应时间、初始U(VI)浓度、吸附剂用量等对AI-g-AO吸附U(VI)的影响。吸附过程运用准一级、准二级动力学模型、Langmuir和Freundlich等温线研究。结果表明,在30℃、初始U(VI)浓度15 mg/L、吸附剂：U(VI)溶液=1 g:1 L、pH为6条件下,U(VI)的最大吸附量为14.98 mg/L。准二级动力学、Langmuir等温线适用于吸附过程。综上,AI-g-AO是一种较好的U(VI)生物吸附材料。