硅载生物吸附剂的制备及性能研究

通过酵母细胞自溶得到中空细胞壁。以硅酸乙酯为原料,制备硅溶胶,通过溶胶-凝胶法制备了粒径为250~600μm的硅载细胞壁生物吸附剂S-1。以环氧氯丙烷交联细胞壁生物吸附剂S-2为对照,比较两者对Ag+的吸附性能。并研究了S-1对Pb2+,Cd2+,Cu2+,Zn2+的吸附性能。结果S-1的吸附强度明显高于S-2,但两者的吸附容量相当。S-1对Ag+及其它金属离子具有较高的吸附强度,对Pb2+和Cd2+具有较大的吸附容量。吸附是由于酵母细胞壁上的多糖对金属离子的螯合作用。     

Intraparticle diffusivity of Cd ions in a new biosorbent material

Cadmium equilibrium sorption isotherms were determined for formaldehyde crosslinked Sargassum fluitans, establishing that an effective regeneration of the new biosorbent material is possible by an acid wash. Batch desorption kinetics were investigated at pH values of 1·0 and 2·0. By incorporating the linear and non-linear Langmuir equilibrium isotherm relationships into the rate equations, a mathematical model was proposed for modeling the metal desorption process. The model was solved numerically and a MATLAB computer program was used to curve-fit the experimental data. The model successfully predicted the Cd²⁺ elution concentration profile in a batch reactor. The average values of the intraparticle diffusivity of Cd²⁺ in the algal biosorbent calculated from the model were 3·40 × 10⁻⁶ and 1·65 × 10⁻⁶ cm² s⁻¹, 0·473 and 0·229 times the molecular diffusivity of Cd²⁺ in water, at pH values of 1·0 and 2·0, respectively. These values agreed well with theoretical predictions.     

四种生物吸附剂对铀的吸附性能研究

以保护环境为目的,以寻求廉价而有效的生物吸附材料为出发点,研究了啤酒酵母菌、北海海草、榕树叶、杉树皮等4种吸附剂对铀的吸附性能的影响。结果表明:4种吸附剂对低浓度铀具有很好的富集作用,其吸附率都在99%以上;每种吸附剂都存在1个最适pH值和1个最佳投放质量浓度,依次对应为4.0—5.0,4—4.5,3.5—4.0,3.0—4.0和10,12,8,10 g/L;4种生物吸附剂对铀吸附符合Freundlich和Langmuir吸附等温方程,且吻合良好;另外4种吸附剂对铀的吸附在吸附量之间存在较大差别,在同一平衡浓度下,吸附量大小顺序为:啤酒酵母菌>榕树叶>北海海草>杉树皮。     

磁性生物吸附剂对Cu2+吸附性能的研究

以环氧氯丙烷为交联剂,用壳聚糖、纳米磁粉悬浮液(Fe3O4)和纯菌丝体制备了磁性生物吸附剂,用XRD对该吸附剂进行了结构表征.研究了溶液pH、吸附时间和Cu2 初始浓度对其吸附性能的影响,结果表明,在pH为5～5.5,Cu2 初始质量浓度为0.1 g/L,吸附时间为8 h的条件下,它的Cu2 去除率为88.73%,吸附容量为16.530 mg/g.该磁性生物吸附剂经5次重复使用后,对Cu2 去除率仍然达到79%以上,具有良好的重复使用性.     

Rapid and Selective Adsorption of Rh(III) from its Solutions Using Cellulose-Based Biosorbent Containing Iminodiacetate Functionality

A new chelating biosorbent with iminodiacetate functionality was prepared. This biosorbent showed a powerful uptake behavior towards Rh(III) from its dilute solutions. The kinetic and thermodynamic characteristics of the uptake process were evaluated using the batch method. The recovery percentage value obtained is comparable to that of a commercial one with the same functionality (Chelest IRY) but with faster kinetics. Fast and selective adsorption of Rh(III) from Pd (II) and Pt(IV) during column experiments makes the resin promising in the field of Rh(III) recovery from the spent catalytic convertors. The adsorbed rhodium was recovered simply by burning the spent resin.     

Recovery of rare earth metals through biosorption： An overview

Rare earth metals (REMs) are a series of 17 elements that have widespread and unique applications in high technology, power generation, communications, and defense industries. These resources are also ...     

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...     

Biosorption of silver from aqueous solutions using wine industry wastes

The potential of wine industry wastes (grape peel, seed, and stem) as alternative biosorbents to remove Ag from aqueous media was investigated in this work. Wine industry wastes were washed, lyophilized and pulverized to obtain the biosorbents. The powdered biosorbents were characterized in detail and several batch experiments were performed to found the most suitable conditions for Ag biosorption. Kinetic, equilibrium, and thermodynamic studies were also performed. The interactions Ag-biosorbent were elucidated by analyses before and after the biosorption. For all wastes, the maximum removal percentages were found using a biosorbent dosage of 3.0?g?L^?1 at pH of 7.0. The kinetic data were well represented by the pseudo-first-order model. The equilibrium was satisfactorily represented by the Sips model. The maximum biosorption capacities, found at 298?K, were: 41.7, 61.4, and 46.4?mg?g^?1 for grape peel, seed, and stem, respectively. Thermodynamically, the biosorption was a spontaneous, favorable, exothermic, and enthalpy-controlled process. The magnitude of ΔH⁰ indicated a physical sorption. These results showed that the wine industry wastes can be considered alternative efficient, low-cost, and eco-friendly biosorbents to remove Ag from aqueous media.     

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.     

絮凝型生物吸附剂ZL5-2对Cr6+的吸附作用研究

本文研究了细菌Agrobacterium.sp产生的絮凝型生物吸附剂ZL5-2对Cr6 的吸附作用。结果表明,ZL 5-2对Cr6 吸附的最佳pH 为0.5-1.5,随着pH增大,吸附作用减弱,pH>3.0后,吸附处于一个低水平的平衡。其他金属离子如Na 、Ca2 、Mg2 、Zn2 、Al3 、K 对吸附作用的影响不大。该吸附过程符合Langmuir和Freundlich等温吸附方程。60 min时吸附达到平衡,Cr6 吸附量可达到37.3 mg/g。被吸附的Cr6 可以被解吸附,解吸率为23.6%～37.9%。