Nickel removal characteristics of an immobilized macro fungus: equilibrium,kinetic and mechanism analysis of the biosorption

BACKGROUND: An immobilized new biosorbent was prepared from macro fungi Lactarius salmonicolor for the effective removal of nickel ions from aqueous media. Operating conditions were optimized as functions of initial pH, agitation time, sorbent amount and dynamic flow rate. Immobilization and biosorption mechanism were examined and the developed biosorbent was tested for the removal of nickel ions from real wastewater. RESULTS: Biosorption performance of the biomass continuously increased in the pH range 2.0–8.0. The coverage of the biosorbent surface by silica gel resulted in a significant increase in biosorption yield of nickel ions. The highest nickel loading capacity was obtained as 114.44 mg g^?1 using a relatively small amount of immobilized biosorbent. Biosorption equilibrium time was recorded as 5 min. Experimental data were analyzed by different isotherm and kinetic models. Infrared spectroscopy, scanning electron microscopy and X‐ray energy dispersive analysis confirmed the process. The sorbent exhibited relatively good recovery potential in dynamic flow mode studies. Biosorption capacity of immobilized biosorbent was noted as 14.90 mg g^?1 in real wastewater. CONCLUSION: Silica gel immobilized biomass of L. salmonicolor is to be a low cost and potential biosorbent with high biosorption capacity for the removal of contaminating nickel from aqueous media. © 2012 Society of Chemical Industry     

Ni(ll) biosorption by Rhizopus arrhizus Env 3: the study of important parameters in biomass biosorption

BACKGROUND: The removal of toxic metals from wastewaters by biosorption, based on the metal‐binding capacities of various biological materials, has attracted much interest. However, the success of this approach depends on economic feasibility, which can be obtained by optimisation of the environmental conditions. In this study, Ni(II) biosorption experiments were carried out using a preformed biomass of Rhizopus arrhizus. A pure culture of previously isolated R. arrhizus Env 3 was used for maximum biosorption of nickel metal from nickel‐electroplating industrial effluent. RESULTS: Various environmental factors such as nickel concentration, pH, temperature, mycelial pellet weight, pretreatment of fungal biomass, dead and living fungal biomass and time course of biosorption by R. arrhizus Env 3 were optimised for maximum removal of nickel from the effluent. The maximum nickel removal rate of 618.5 mg g^?1 was observed with living biomass at pH 8, temperature 35 °C, nickel concentration 500 mg L^?1, pellet size 3 g wet weight and shaker velocity 150 rpm. Maximum nickel biosorption was obtained after 72 h. CONCLUSION: Statistical analysis of different factors such as temperature, pH, mycelial pellet size, concentration of nickel in effluent and residual nickel level showed that all these factors had significant effects on the biosorption of nickel metal by R. arrhizus Env 3 from nickel‐electroplating industrial effluent. Copyright © 2008 Society of Chemical Industry     

Recovery of uranium by tannin immobilized on matrices which have amino group

Tannin, which contains polyhydroxy groups, has a high affinity for uranium. Various tannin–protein complexes were prepared to develop new adsorbents for uranium recovery from seawater. Albumin tannate has a high ability to adsorb uranium from seawater. Tannin was immobilized on matrices which have multiple active amino groups, such as aminopolystyrene and poly(vinyl-4,6-diamino-s-triazine)—poly VT. Of these complexes, tannin immobilized on poly VT adsorbed uranium most efficiently from seawater and highly selectively from a solution containing various heavy metals; the uranium adsorption was very rapid and was pH dependent. This adsorbent therefore appears to have potential for use in a commercial process for uranium recovery from seawater or from uranium-containing waste water.     

芝麻叶对亚甲基蓝吸附的动力学与热力学研究

以天然芝麻叶为吸附剂,亚甲基蓝(MB)为吸附质,考察芝麻叶吸附亚甲基蓝的动力学、热力学以及溶液pH值、吸附剂投入量、温度等对吸附的影响.采用准一级、准二级、颗粒内扩散吸附动力模型及Langmuir,Freundlich及Dubinin-Radushkevich(D-R)等温模型分别对吸附动力学和吸附等温线进行分析.结果...     

Kinetics of nickel biosorption by acid‐washed barley straw

This work reported the rate of nickel biosorption using acid‐washed barley straw (AWBS) at different initial nickel concentration, AWBS particle size, solution pH, and temperature. The biosorption process was rapid and the equilibrium was reached in about 100 min with initial nickel concentrations from 250 to 1000 mg/L. AWBS with particle size of <0.425 mm exhibited a greater adsorption rate and reached equilibrium faster than particle sizes of 0.425–1.18 mm. An increase in pH from 3.0 ± 0.1 to 7.0 ± 0.1 increased the rate of adsorption and resulted in a higher equilibrium nickel uptake. Nickel adsorption was more favourable at 23 ± 1°C compared to 5 ± 1°C and 40 ± 1°C. The external mass transfer model was able to fit the dynamic nickel biosorption data and provided acceptable overall volumetric mass transfer coefficients.     

生物吸附法去除水中重金属离子

生物吸附作为一种有效的去除水中重金属的方法引起人们的极大关注。近几年虽然提出了许多吸附模型,但生物体的吸附机理尚不完全清楚。生物吸附过程受生物体本身的性质、处理水的种类、离子强度、pH、反应动力学、反应设备等因素的影响。由于生物体在吸附和脱吸过程中具有非常好的可逆性．并且这种生物体大量存在,因此在水处理领域具有非常好的应用前景。作者主要介绍了近几年国外生物吸附法在水处理方面的研究成果。     

Ionic Competition Effects in a Continuous Uranium Biosorptive Recovery Process

Immobilized Rhizopus arrhizus biomass was studied in a continuous sorption and desorption mode in order to identify factors that affect the long term uranium biosorptive uptake capacity performance of the immobilized biomass. Laboratory-scale continuous operation pilot plant experiments were performed using synthetic uranyl nitrate and industrial uranium mine leachate solutions. Analysis of the liquid solutions indicated that the immobilized Rhizopus arrhizus biomass successfully recovered all of the uranium from the dilute (less than 500 mg U dm⁻³) solutions. All uranium can subsequently be eluted, yielding highly concentrated uranium eluates. The immobilized Rhizopus arrhizus biomass maintained its uranium biosorptive uptake capacity over 12 successive sorption–elution cycles when synthetic uranyl nitrate solutions were used. However, when used with mine leachate solutions, an 18% reduction in the uranium biosorptive uptake capacity occurred within the first four adsorption–elution cycles. Spectral analysis indicated that, during continuous use and reuse, the immobilized biomass retained its structural integrity. EDAX, scanning and transmission electron microscopic techniques employed on the microbial biomass suggested that the presence of aluminium interferes with the uranium biosorption process. Spectral analysis also indicated that the presence of silicon enhances the negative effect of the presence of aluminium on the uranium biosorptive uptake capacity of the immobilized Rhizopus arrhizus biomass particles. © 1997 SCI     

基于甘蔗渣生物吸附重金属污染物的研究

用甘蔗渣作为生物吸附质,研究了甘蔗渣对水中铅铜离子吸附能力及影响因素,探讨了吸附质粒径、pH值、吸附时间和投加量等因素对铅离子和铜离子吸附的影响。结果表明:甘蔗渣吸附两种重金属的适宜粒径应大于140目,适宜pH为4~6,超过7则因氢氧化物沉淀生成而影响吸附;甘蔗渣对两种重金属的吸附很快,1.5 h就近乎达到衡;甘蔗渣对铅的吸附性能要优于铜,对铅最大吸附量可以达到41.32 mg/g,去除率为91.83%,对铜的最大吸附量可达到30.62 mg/g,去除率为68.05%;同时甘蔗渣对铅和铜的竞争吸附实验表明,铅和铜对甘蔗渣上基团的吸附存在竞争使得吸附量相对于正常条件下有较大的降低。     

啤酒酵母吸附去除水中Cd~(2+)的影响因素

生物吸附法是一种经济有效的处理大规模低浓度重金属废水的生物技术,其中啤酒酵母(Saccharomyces cerevisiae)是具有实用潜力的生物吸附剂。本文研究了啤酒酵母对Cd2+吸附效果的主要影响因素,结果表明pH值对Cd2+会产生较大的影响,非固定化和固定化啤酒酵母对Cd2+吸附的最佳pH值都为4,过高和过低均不利于吸附的进行。水中常见的K+、Ca2+、Na+、Mg2+四种离子在低浓度时对Cd2+的吸附无显著影响,但当其浓度高于5mg/L时会影响吸附,其影响顺序为K+Na+Ca2+Mg2+;Zn2+、Fe2+、Cu2+、Pb2+对Cd2+的吸附效果影响顺序为Pb2+Zn2+Fe2+Cu2+;当Cu2+浓度≥50mg/L时,啤酒酵母对Cd2+不产生性吸附,而对Cu2+产生专性吸附。     

The biosorption of Cr(VI) ions by dried biomass obtained from a chromium-resistant bacterium

The biosorption potential of many different kinds of biomaterials has been widely studied. However, there is little data on the biosorption mechanism of Cr(VI) by dried biomass. So the bio-removal of Cr(VI) ions from aqueous solutions was investigated using dried biomass from a chromium-resistant bacterium. The bacterium was isolated from dewatered sludge samples that were obtained from a sewage treatment plant. Equilibrium and kinetic experiments were performed at different metal concentrations, pH values, and biosorbents dosages. The biomass was characterized using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The functional groups in the Bacillus cereus biomass which may play a role in the biosorption process were identified by Fourier transform infrared spectroscopy. The biosorption process was found to be highly pH dependent and the optimum pH for the adsorption of Cr(VI) was 2.0±0.3 at 30±2 °C. The experimental data fit well with Langmuir and Freundlich models as well as a pseudo-second order kinetic model. The mechanism for the biosorption was also studied by fitting the kinetic data with an intra-particle diffusion model and a Boyd plot. External mass transfer was found to be the rate-determining step for the adsorption process. Biosorption could be an alternative mechanism besides bio-oxidation and bio-reduction for the bioremediation of heavy metals.     

Adsorption of Cu(II) from aqueous solutions by tannins immobilized on collagen

Novel adsorbents were prepared by immobilizing tannins on collagen fibre matrices. Their adsorption properties, including adsorption equilibrium, adsorption kinetics, and column adsorption kinetics to Cu(II) were investigated. Immobilized Myrica rubra tannin and black wattle tannin exhibited significantly higher adsorption capacity than larch tannin and the adsorption isotherms of these three immobilized tannins can be described by the Freundlich model. Detailed adsorption studies of immobilized black wattle tannin to Cu(II) indicated that temperature had little effect on the adsorption isotherms whereas the effect of pH was significant. Adsorption rate data fitted well to a pseudo‐second‐order rate model, and the adsorption capacity calculated by this model was consistent with the result of actual measurement at relatively higher adsorption temperatures. Immobilized black wattle tannin also had excellent column adsorption kinetic properties and high binding capacity. The adsorptivity of the column was stable even after repeated adsorption–desorption cycles. Copyright © 2004 Society of Chemical Industry     

固定化啤酒废酵母对pb2+吸附性能的研究

固定化啤酒酵母法是采用啤酒废酵母作为生物吸附剂,研究其在固定化的条件下对Pb2+的吸附特性。用2%海藻酸钠与1%明胶混合作为包埋剂固定啤酒废酵母。考察了固定化啤酒废酵母吸附Pb2+过程中的影响因素,包括初始Pb2+浓度、酵母菌体浓度、吸附时间和初始pH值等。试验结果表明,在初始Pb2+质量浓度为100mg/L、pH值为5、菌体酵母投加量为1.44 g/L、吸附时间为180 min的最佳条件下,固定化啤酒废酵母对Pb2+的吸附率为92.69%,吸附量为51.35 mg/g,吸附符合Freunollich方程,相关系数R为0.990 14。     

磁可分固定化漆酶降解甲基橙反应条件的考察

本文以Fe3O4/SjO2纳米复合粒子固载的漆酶降解甲基橙染料,研究了初始溶液的pH值、反应温度、介体ABTS的投加量、作用时间等因素对甲基橙溶液脱色率的影响,同时还考察了催化剂的重复使用性能.结果表明,该固定化漆酶降解甲基橙溶液时对pH值、反应温度、作用时间和介体ABTS的用量有一定的要求,在理想的反应条件下甲基橙的...     

生物质颗粒孔隙结构在热解过程中的变化

利用氮气等温吸附/脱附法（-196℃）和扫描电镜（SEM）等研究了热解过程中生物质颗粒孔隙结构的演化规律,并用分形维数来描述焦颗粒内部孔隙表面形态的复杂程度。结果表明,热解温度对生物质焦的孔结构和表面形态有显著影响。热解过程中孔网络结构在发生演变,孔的形状发生了一定变化,且孔径有先变小后变大的趋势。高温导致焦颗粒发生塑性变形,使得孔隙扩大和孔表面更加光滑。随着温度的升高,生物质焦的BET比表面积先增大后减小,500℃以前,孔容积的变化规律与比表面积相近。通过分形FHH方程回归得到的分形维数能较好地表征颗粒内部孔隙表面的分形特征。其分形特征与热解温度密切相关,分形维数的变化与BET比表面积有一定关联。     

Study on the kinetics of hazardous pollutants adsorption and desorption by biomass: Mechanistic considerations

The kinetics of biosorption and desorption of lindane, diazinon and 2-chlorobiphenyl by inactive activated sludge and Rhizopus arrhizus biomass was studied. The effects of solution initial concentration, temperature and type of biomass on the observed biosorption and desorption rates were also examined. The results of the present work show that the biosorption rates are reasonably rapid, with equilibrium attained within 4 h by activated sludge and 1 h by R. arrhizus. The observed biosorption kinetics consist of a rapid initial stage followed by a slower second stage. The observed rate of organic pollutants biosorption by activated sludge during the first stage can be described by second order kinetics. The biosorption of lindane by both biomass types is reversible and the desorption process is rapid and could be described by zero order kinetics when activated sludge is used as adsorbent. The type of biomass can have a significant effect on the observed biosorption and desorption rates.     

Modelling of the pyrolysis of biomass particles. Studies on kinetics,thermal and heat transfer effects

The present work provides a rationally-based model to describe the pyrolysis of a single solid particle of biomass. As the phenomena governing the pyrolysis of a biomass particle are both chemical (primary and secondary reactions) and physical (mainly heat transfer phenomena), the presented model couples heat transport with chemical kinetics. The thermal properties included in the model are considered to be linear functions of temperature and conversion, and have been estimated from literature data or by fitting the model with experimental data. The heat of reaction has been found to be represented by two values: one endothermic, which prevails at low conversions and the other exothermic, which prevails at high conversions. Pyrolysis phenomena have been simulated by a scheme consisting of two parallel reactions and a third reaction for the secondary interactions between charcoal and volatiles. The model predictions are in agreement with experimental data regarding temperature and mass-loss histories of biomass particles over a wide range of pyrolysis conditions.