吸附法处理重金属废水污染的研究进展

重金属在环境中只能迁移和转化,不能够被降解,因此重金属被排入到环境中以后,会严重破坏生态环境,对动植物和人体健康造成威胁。目前,重金属废水处理已成为急需解决的问题之一,为此需要合理应用现代化技术手段使其能够做到无害化排放,常见技术方法包括沉淀法、吸附法、电化学法、膜分离法等,其中吸附法因其耗资更少、操作简单,为此被广泛应用于重金属废水污染处理中,以此为后续领域发展提供帮助。通过吸附法处理重金属废水,最为关键的是得到高性能、低成本的吸附剂,本文对吸附法处理重金属废水的原理进行了分析,并且对吸附剂在处理重金属废水的研究进展进行了介绍,探讨吸附法处理重金属废水的机理,包括物理吸附、化学吸附和生物吸附三个部分,随后分析了重金属废水所用吸附剂,包括碳基吸附剂、纳米材料吸附剂、矿物吸附剂、高分子吸附剂以及生物吸附剂,切实提高重金属水污染的处理效果,以期能够为相关人员提供参考和借鉴。     

香兰素修饰的吸附树脂对水中尿囊素的吸附研究

文章通过静态吸附实验和吸附动力学实验研究了香兰素修饰的吸附树脂(XLS-01)对尿囊素的吸附性能,计算了该吸附过程中的吸附热力学和吸附动力学,分析了尿囊素在XLS-01树脂上的吸附机理。     

废水重金属的生物吸附研究进展

生物吸附法是目前处理重金属废水的一种行之有效的方法,特别是对于低浓度废水,其优势明显,还可达到以废治废的目的。对废水重金属的生物吸附进行了综述,详细介绍了目前最具代表性的四种生物吸附机理以及已经开发出来的五种吸附工艺,同时还探讨了影响生物吸附重金属的多种因素和生物吸附剂的类型,展望了生物吸附废水中重金属在工业生产中的应用前景。     

程序升温脱附测定难挥发性有机物吸附相平衡

提出一种采用少量程序升温脱附实验就能计算挥发性有机物在不同温度下吸附等温线的方法.该方法以拟平衡吸附动力学为基础,建立难挥发性有机物从吸附剂表面程序升温脱附的模型,采用数值方法对该模型进行求解.采用该模型对程序升温脱附实验测定的图谱进行模拟,获得难挥发性有机物在吸附剂上的吸附相平衡参数,从而确定吸附等温线.运用所提出的...     

生物吸附在含重金属废水处理中的研究进展

生物吸附法是目前处理含重金属废水最有前途的方法之一,尤其在处理含1~100mg/L的重金属废水时特别有效。详细介绍了生物吸附的机理、不同种类微生物对重金属的吸附特性,并对影响生物吸附过程的各种因素进行了讨论,最后对生物吸附重金属的发展方向进行了预测。     

吸附热预测吸附等温线

实验测定了N2 在沸石分子筛、C2 H6 在活性炭、CO2 在硅胶上的吸附等温线 ,研究用Clausius Clapeyron方程求得等量吸附热、再利用所得的吸附热预测其它温度的吸附等温线数据的方法。将吸附热预测的等温线与实验值及插值法内插得到的吸附等温线数据进行了比较 ,结果表明吸附热预测值与实验值吻合较好。此外还对文献数据利用等量吸附热预测较高压力 ( 65 0kPa)下的等温线 ,均与文献中的实验值一致。为吸附工业操作需要不同温度下的等温线数据和吸附过程的模拟与设计提供了简便、准确的计算方法     

基于电化学技术检测微生物吸附

为研究微生物在固体表面吸附的过程,探索微生物黏膜的形成机理,采用电化学交流阻抗法对铜电极表面黏液形成菌吸附形成的生物黏膜进行表征,实验结果表明：由实验数据拟合出的等效电路与根据理论分析而设计出的等效电路基本吻合,通过测量生物膜电容计算出的生物黏膜厚度为1.8 μm,与用SEM观测显示的黏膜厚度基本一致,由此说明了用交流阻抗表征生物膜的可行性和微生物在固体表面吸附传质成膜过程分析的正确性,该方法为探索微生物黏膜的形成机理提供了有力的检测手段,并对静态下实时监测生物黏膜的形成具有重要意义。     

衣藻对重金属生物吸附的实验研究

以衣藻为生物吸附材料,研究了它对重金属钴、铜、锌的生物吸附,并用Freundlich等温吸附方程对实验数据进行处理。结果表明衣藻对这三种金属吸附能力大小顺序为锌钴铜;农藻对重金属的吸附能力很强,可用衣藻来处理含重金属的废水。     

农林废弃物吸附脱除废水中重金属研究进展

含重金属的工业废水对环境的危害是相当巨大的,生物吸附法可有效去除废水中的重金属.本文总结了常见的农林废弃物和化学改性剂在吸附重金属方面的研究现状,指出了生物吸附的影响因素及吸附工艺优化,阐述了生物吸附法的吸附机理及解吸处理,介绍了生物吸附的热力学和动力学模型及相关参数,同时指出了生物吸附法存在的问题,并展望其未来的发展前景.农林废弃物具有来源广、成本低、可再生等优点,用于重金属废水处理时,可实现资源的综合利用,具有良好的工业前景.     

磁性生物炭的制备及其对重金属吸附研究进展

生物炭因比表面积大、孔隙率发达、表面官能团丰富等特点,常被用于吸附水体中的重金属杂质.但在水溶液介质中难于分离,需要对其改性.对生物炭进行赋磁改性可以增加其吸附量,便于回收利用.本文主要综述了利用不同的生物质原料,采用不同的方法制备出磁性生物炭(MBC),探究了磁性生物炭对水体中重金属离子的吸附机理,对未来研究磁性生物...     

A model for ph dependent equilibrium of heavy metal biosorption

Biosorption of heavy metals can be an effective process for the removal and recovery of heavy metal ions from aqueous solutions. The biomass of marine macro algae has been reported to have high uptake capacities for a number of heavy metal ions and the uptake capacities are strongly influenced by the value of the solution pH. In this paper, a modified Langmuir model was proposed for describing the pH dependent biosorption equilibrium and validated with isotherm data obtained from batch experiments and from the literature. The model assumes that the functional groups for heavy metal interactions are weakly acidic and the uptake capacities of the biomass are affected through the association and dissociation equilibrium between two apparent ionic forms. The model equations fitted the experimental data well, which supports the biosorption mechanism proposed.     

Removal of Cu(II), Cr(III), and Cr(VI) from Aqueous Solution using a Novel Agricultural Waste Adsorbent

A novel adsorbent, chufa corm peels (CCP), is used for removing Cu(II), Cr(III), and Cr(VI) from aqueous solutions. The adsorption ability and characteristics of the CCP are thoroughly investigated. The adsorption capability for three heavy metal ions is in the order of Cu(II) > Cr(III) > Cr(VI). The morphology and elemental distribution on the biomass of CCP were evaluated by scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). Fourier-transform infrared spectroscopy (FTIR) analysis revealed that oxygen-containing functional groups, especially carboxylic and hydroxyl groups were responsible for chemical coordination between ionizable functional groups and metal ions. The adsorption features were evaluated based on the batch biosorption experiment. The results showed that the adsorption well meets the Freundlich adsorption isotherm models and pseudo-second-order kinetics model. In summary, this work demonstrated that CCP is an attractive, efficient, and low-cost adsorbent biomaterial that can be used for the removal of heavy metals from environmental contaminations.     

ADSORPTIVE TREATMENT OF CYANIDE-BEARING WASTEWATER: A PROSPECT FOR SUGAR INDUSTRY WASTE

The biosorption of cyanide ions from aqueous solution by bagasse was studied in a batch adsorption system with pH, contact time, cyanide ion concentration, metal ion concentration, and adsorbent dosage as variables. XRD, FT-IR spectroscopy, CHN, proximate, ultimate, and TG/DTG thermal analyses were used for the characterization of bagasse. The biosorption capacities and rates of biosorption of cyanide ions onto bagasse were evaluated. The Langmuir and Freundlich adsorption models were applied to describe the isotherms and isotherm constants. Biosorption isothermal data were interpreted by the Langmuir model followed by the Freundlich model with maximum adsorption capacity of 98% of cyanide ion on bagasse. The kinetic experimental data were properly correlated with the first- and second-order kinetic model.     

Adsorption performance of nickel and cadmium ions onto brewer's yeast

The brewer's yeast was used as adsorbent for the removal of Ni(II) and Cd(II) metal ions from aqueous solution. The surface of the brewer's yeast had three main functional groups of sulfonate, carboxyl, and amine groups. The pH of solution played an important role on the uptake of metal ions, and optimum adsorption was obtained at pH 6. Acid solution (pH 3) was efficient for the desorption of Ni(II) and Cd(II) ions from loaded brewer's yeast and the desorption efficiency was higher than 90%. The rate of metal ions adsorption onto brewer's yeast was rapid with short contact time. The kinetics of the adsorption process was found to follow the pseudo‐second‐order kinetic model. Langmuir and Freundlich isotherm models were used to fit the experimental data with Langmuir isotherm model having a better fit. The maximum uptakes of Ni(II) and Cd(II) by brewer's yeast were estimated to be 5.34 and 10.17 mg/g, respectively.     

Cu(II) ions removal from wastewater using starch nanoparticles (SNPs): An eco-sustainable approach

The complex structured starch particles were reduced to the nanoscale size range through hydrolysis utilizing low concentration acid assisted by ultrasound irradiation. The synthesized starch nanoparticles (SNPs) were characterized by transmission electron microscopy (TEM), Fourier-transform infrared (FTIR), and X-ray diffraction (XRD) techniques. The synthesized SNPs possessed surface activated entities, as many cationic functional groups were confirmed through the FTIR spectrum. Also, these SNPs were effectively utilized to separate heavy Cu metal ions from the synthetic ion solution. The SNPs were characterized using field emission scanning electron microscope (FESEM), X-ray photoelectron spectroscopy (XPS), and Brunauer–Emmett–Teller (BET) analysis for the surface modification after the adsorption process. The weak electrostatic interaction between the SNP surface and Cu ion was confirmed by the XPS spectrum and energy-dispersive X-ray spectroscopy. The maximum efficiency of Cu ions removal was about 93% at an optimal pH 5 and 25 mg/ml dosage. The adsorption equilibrium was obtained in 60 min. The nitrogen isotherm BET analysis of SNPs after adsorption shows a higher specific surface area of 18.552 m²/g, attributed to the interaction and presence of Cu ions on the SNP surface. The process feasibility was validated by the Langmuir isotherm model. The process exhibits pseudo-second-order adsorption kinetics and follows the Langmuir isotherm. The R_L predicted by the Langmuir isotherm mechanism is 0.017, implying favourable adsorption. The process is reproducible and allows for the separation of heavy metal ions from the wastewater through biosorption effectively.     

Cadmium biosorption by a glyphosate-degrading bacterium,a novel biosorbent isolated from pesticide-contaminated agricultural soils

In this study, biosorption of cadmium (II) ions from aqueous solutions by a glyphosate degrading bacterium, Ochrobactrum sp. GDOS, was investigated in batch conditions. The isolate was able to utilize 3 mM GP as the sole phosphorous source, favorable to bacterium growth and survival. The effect of different basic parameters such as initial pH, contact time, initial concentrations of cadmium ion and temperature on cadmium uptake was evaluated. The adsorption process for Cd (II) is well fitted with Langmuir adsorption isotherm. Experimental data were also tested in terms of biosorption kinetics using pseudo-first-order and pseudo-second-order kinetic models. Maximum metal uptake q_max was obtained as 83.33 mg g⁻¹. The sorption process of cadmium onto the Ochrobactrum sp. GDOS biomass followed second-order rate kinetic (R² = 0.9986). A high desorption efficiency was obtained in pH 2. Reusability of the biomass was examined under successive biosorption–desorption cycle repeated thrice. The characteristics of the possible interactions between biosorbent and metal ions were also evaluated by scanning electron microscope (SEM), Fourier transform infrared (FT-IR) and X-ray diffraction analysis.     

Interaction of stevensite with Cd2+ and Pb2+ in aqueous dispersions

The experimental process of adsorption of Pb(II) and Cd(II) onto clay mineral is studied here in order to evaluate the capacity for removal for these two heavy metal ions. This study is performed under various conditions such as initial solution pH, chemical clay modification conditions, initial metal ion concentration and contact time. The experimental isotherm data are analysed using Temkin, Langmuir and Freundlich equations and it is shown that models produce comparable equilibrium correlation results. The isotherm curves show very clearly the selectivity of the clay for the lead ions but also significant amounts of cadmium are removed as well. Adsorption kinetics data were tested using pseudo-first-order and Intraparticle diffusion models. Adsorption mechanism studies revealed that the process was complex and followed both surface adsorption and particle diffusion. The rate-controlling parameters and diffusion coefficients were determined using the Crank and McKay diffusion models. It was found that the adsorption occurs through film diffusion and the particle diffusion becomes the rate-determining step for each metal ion.     

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.     

Recovery of Thorium by High-Capacity Biopolymeric Sorbent

The potential of prepared alginate biopolymers as a natural, economic, effective, non-toxic biosorbent was investigated for the recovery of thorium ions in this study. The experiments were carried out to study the effects of various physico-chemical parameters on biosorption and desorption of thorium. The biosorption process was examined by various isotherm models and equilibrium data were successfully described by a Langmuir model very well. The monolayer biosorption capacity was found as 169.50 mg/g. The thermodynamic parameters such as variations of enthalpy, entropy, and Gibbs free energy for thorium biosorption were also defined and the results suggest that endothermic nature of the process. The prepared alginate biopolymers exhibit high uptake capacity and regeneration potential for biosorption of thorium.