Patent abstracts

This paper gives an overview of the feasibility of the application of biotechnology to nuclear waste treatment. The contents are based on a report which PA Technology carried out for the Department of the Environment (DoE Reference: DoE/RW/88.008 Sector No 2.3). Many living and dead organisms accumulate heavy metals and radionuclides. The controlled use of this phenomenon forms the basis for the application of biotechnology to the removal of radionuclides from nuclear waste streams. Indeed, biotechnology offers a series of new opportunities for removal of radionuclides from dilute aqueous process effluents. Such technology is already used for heavy metal removal on a commercial basis and could be optimised for radionuclide removal. An overview of biotechnology areas, namely the use of biopolymers and biosorption using biomass applicable to the removal of radionuclides from industrial nuclear effluents is given. The potential of biomagnetic separation technology, genetic engineering and monoclonal antibody technology is also to be examined. The most appropriate technologies to develop for radionuclide removal in the short term appear to be those based on biosorption of radionuclides by biomass and the use of modified and unmodified biopolymers in the medium term.     

生物质吸附材料对Cr(VI)的吸附还原研究进展

重金属污染是当今工业发展所面临的一个重要环境问题,传统处理含铬废水的方法具有工艺简单、操作方便等优点,但存在二次污染、处理成本高等问题。寻找成本低、去除效率高的重金属废水处理方法是当下研究的一个重要方向。本工作介绍了生物质吸附法对含铬废水的处理研究,简述了生物质材料在金属吸附回收领域的优势,分析了当前生物质吸附材料的研究内容和发展现状,归纳了目前常用的物理、化学改性方法,并详细介绍了改性生物质材料对Cr(VI)的吸附效果,然后根据吸附剂表面活性基团与吸附质之间相互作用的类型,分析总结了生物质吸附材料对Cr(VI)的四种吸附机理以及在吸附过程中氨基、羟基、硫醇等活性基团作为电子供体对Cr(VI)的还原机理。最后,从研究与应用的角度,对生物质吸附材料吸附还原Cr(VI)的未来研究方向做出展望。     

Kinetic and Equilibrium Modeling of Pb(II) and Co(II) Sorption onto Rose Waste Biomass

Abstract

An attempt was made to assess the biosorption potential of rose waste biomass for the removal of Pb(II) and Co(II) ions from synthetic effluents. Biosorption of heavy metal ions (>90%) reached equilibrium in 30 min. Maximum removal of Pb(II) and Co(II) occurred at pH 5 and 6 respectively. The biosorbent dose for efficient uptake of Pb(II) and Co(II) was 0.5 g/L for both metals. The biosorbent size affected the Pb(II) and Co(II) biosorption rate and capacity. Rose waste biomass was found effective for Pb(II) and Co(II) removal from synthetic effluents in the concentration range 10–640 mg/L. Equilibrium sorption studies showed that the extent of Pb(II) and Co(II) uptake by the rose waste biomass was better described by the Langmuir isotherm in comparison to the Freundlich model. The uptake capacities of the two metal ions were 156 and 27.15 mg/g for Pb(II) and Co(II) respectively.     

Biosorption of Zn(II) by orange waste in batch and packed‐bed systems

BACKGROUND: This research provides new insights into the biosorption of zinc on a waste product from the orange juice industry. Optimal operating conditions maximizing percentage zinc removal were determined in batch and fixed‐bed systems. Biomass was characterized by FTIR spectroscopy and by major cation content in order to better understand the biosorpion mechanism. Zn‐loaded orange waste was proposed to be used as an alternative fuel in cement kilns. RESULTS: Sorption capacity was strongly affected by biosorbent dose and solution pH, and was not strongly sensitive to particle size under the experimental conditions studied. Equilibrium data were successfully described by a Langmuir model and sorption kinetic data were adequately modelled with the pseudo‐second‐order and Elovich rate equation. The biomass was found to possess high sorption capacity (q_max = 0.664 mmol g^?1) and biosorption equilibrium was established in less than 3 h. Experimental breakthrough curves were adequately fitted to the Thomas model and the dose–response model, obtaining sorption capacities in continuous assays higher than those found in batch mode. Characterization of the biomass suggested the possible contribution of carboxyl and hydroxyl groups of biomass in Zn²⁺ biosorption and it also highlighted the important role of light metal ions in a possible ion‐exchange mechanism. CONCLUSIONS: Orange waste could be used as an effective and low‐cost alternative biosorbent material for zinc removal from aqueous solution. Copyright © 2010 Society of Chemical Industry     

Biosorption of lead (II) from aqueous solution by cone biomass of Pinus sylvestris

Biosorption of lead (II) onto a cone biomass of Pinus sylvestris was studied with variation in the parameters of pH, initial metal ion concentration and impeller speeds. Lead removal rate was increased at pH 4.0 and was sharply decreased when pH of the solution was decreased to 2.0. Impeller speed studies indicated maximum lead biosorption at 150 rpm and the biosorption equilibrium was established after about 1 h. The adsorption constants were found from the Freundlich isotherm at 25°C. An increase in lead/biomass ratio caused a decrease in biosorption efficiency. The cone biomass, which is a readily available biosorbent, was found suitable for removing of lead in aqueous solution.     

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     

Sugar-beet pulp pectin gels as biosorbent for heavy metals: Preparation and determination of biosorption and desorption characteristics

The present work reports the feasibility of using sugar-beet pectin gels for the removal of heavy metals from aqueous solutions. Sugar-beet pectin hydro- and xerogels were tested in the batch biosorption and desorption of cadmium, lead and copper. Pectins were successfully extracted and demethylated from the sugar-beet pulp, an agricultural residue, and gelled in the presence of CaCl₂. The stability of the hydro- and xerogel pectin beads made them suitable for biosorption of heavy metals in different conditions. Biosorption data were fitted to the pseudo-second order kinetic model and the Langmuir isotherm model, obtaining the corresponding parameters. Treated and untreated beads were characterized using FTIR and SEM to determine possible binding mechanisms. The main mechanisms involved were ion exchange with calcium of gel structure and chelation or complexation with carboxyl groups. After biosorption, calcium in the gels was substituted by metal cations reorganizing the structure of the gel matrix in a way that was visible using scanning electron microscopy. HNO₃ 0.1 M was the best eluant for the reutilization of the gels and recovered all the adsorbed metal unlike HCl and H₂SO₄. Sugar-beet pectins could be used as an efficient biosorbent for the treatment and recovery of Cu, Pb and Cd from wastewater.     

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.     

Biosorption of Chromium from Effluent Generated in Chrome‐Electroplating Unit using Saccharomyces cerevisiae

Abstract

Biosorption of chromium from effluent generated in chrome‐electroplating unit using waste yeast biomass Saccharomyces cerevisiae was carried out. Chromium concentration in the effluent was 204 mg/L. Chromium biosorption equilibration time was found to be 2 hours, with uptake of 6.607 mg/g. Biosorption increased with rise in pH and chromium concentration. Equilibrium biomass concentration and agitation speed were 2% and 150 rpm, respectively. The biosorption equilibrium data fit with Freundlich and Langmuir isotherm models revealed K_f and Q_max values of 0.3727 and 384.61 mg/g, respectively.     

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。     

Biotechnology group meeting. Biochemistry and genetics for increasing productivities of industrial fermentation

Biosorption of heavy metals by microbial cells has been recognized as a potential alternative to existing technologies for removing heavy metals from industrial waste waters. Many aquatic microorganisms, such as algae, can take up dissolved metals from their surroundings to their cells. In this study, the adsorption of lead(II) ions was investigated in a single-staged batch reactor. Chlorella vulgaris, a green alga, was used as the sorbent. The sorption phenomenon was expressed by the Freundlich adsorption isotherm and this expression was used for the calculation of residual or adsorbed metal ion concentration at equilibrium (C_eq or C_x,eq) at a given ‘volume of waste water containing heavy metal ion/quantity of alga (V₀/X₀)’ ratio in a single-staged batch reactor. Experimental C_eq and C_x,eq values were compared to calculated ones. Applications in waste water treatment for lead(II) removal have been suggested.     

Biosorption of thorium from aqueous solution by Ca-pretreated brown algae Cystoseira indica

The potential use of a biosorbent, Cystoseira indica, obtained from the Persian Gulf was investigated for the removal of Th (IV) ions from aqueous solutions by considering equilibrium, kinetic and thermodynamic aspects. The FT-IR spectra of unloaded and Th-loaded biomass indicated various functionalities on the biomass surface including hydroxyl, amide and carboxyl groups, which are responsible for the binding of thorium ions. Th (IV) uptake by C. indica was pH dependent. An increase in biosorbent dosage up to 1 g/L caused an increase in the Th (IV) percentage removal. Biosorption process at all studied initial Th (IV) ion concentrations follows the pseudo-second order kinetic model. The biosorption data could be well described by Redlich-Peterson isotherm in comparison to Langmuir and Freundlich isotherms. The maximum sorption capacity of Th (IV) by Langmuir isotherm was estimated to be 169.49 mg/g at 45 °C with pH of 3. The thermodynamic parameters indicated the biosorption of Th on the biomass was a feasible, spontaneous and endothermic process. Th sorption capacity remained unaffected or slightly affected (<10% inhibition) in the presence of several interfering ions such as uranium (VI), nickel (II) and copper (II). The reusability of the biomass was also determined after five sorption-desorption cycles.     

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.     

垃圾焚烧飞灰在污染物控制领域中的应用探讨

随着垃圾焚烧处置技术的推广和应用，垃圾焚烧飞灰产量逐年增加，传统填埋处置方式存在成本高、填埋场资源不足等问题，因此飞灰的综合利用问题广受关注。由于飞灰富含SiO₂、Al₂O₃等活性物质，在污染物的吸附脱除领域具有良好的应用前景。本文主要结合垃圾焚烧飞灰的理化特性，介绍了垃圾焚烧飞灰在不同废水废气中的污染物吸附脱除效果。综合近年来污染物脱除研究情况，着重介绍了原始飞灰和改性飞灰在重金属、磷盐、染料等污染物脱除中的应用效果、机理，指出了目前存在的主要问题，并对不同的应用工艺进行了成本分析和优缺点对比。最后提出了需要继续深入微波水热在提高飞灰吸附性的应用研究和进一步完善飞灰在污染物控制领域应用的全过程研究的建议与展望。     

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     

Removal of lead and cobalt using lignocellulosic fiber derived from <Emphasis Type="Italic">Citrus reticulata</Emphasis> waste biomass

The present investigation explored the use of Citrus reticulata waste biomass (CWB) for the removal of Pb(II) and Co(II) from the aqueous solutions. The Pb(II) and Co(II) biosorption was found to be dependent on pH of the solution, biosorbent dose, biosorbent particle size, temperature, shaking speed, contact time and initial concentration of metal ions. A metal uptake capacity of 41.16 and 52.64 mg/g was observed at pH 5 and 7 for Pb(II) and Co(II), respectively. The biosorption data followed the Freundlich model for both metals. The overall biosorption process was best described by pseudo-second order kinetics. The effect of several pretreatments on the biosorption efficiency of CWB was also investigated. The results demonstrated that pretreatments influenced the biosorption capacity of the biomass for the both metals significantly. Maximum biosorption capacity of 83.77 and 95.55 mg/g was observed for Pb(II) and Co(II) with sodium hydroxide treated and simply heated biomass, respectively. FTIR spectrum indicated the presence of -OH, -NH, -COOH groups in the biomass. The surface structure of CWB was analyzed by JEOL JMT 300 scanning electron microscope (SEM), and the existence of metal ions on the surface of biosorbent was determined by energy dispersive X-ray (EDX) spectroscopy.     

沸石在污水处理中的应用研究进展

沸石是一种具有优异的吸附及离子交换性能的硅铝酸盐矿物,其在环境治理中有着广泛的应用前景.介绍了沸石在环境领域内尤其是在污水处理中的应用研究进展,重点总结了沸石在去除水中氨氮、有机污染物、重金属离子、放射性物质、氟等方面的应用.     

Equilibrium,Thermodynamic and Kinetic Studies on Biosorption of Mercury from Aqueous Solution by Macrofungus (Lycoperdon perlatum) Biomass

The present research is to investigate the possibility of macrofungus Lycoperdon perlatum biomass, which is an easily available, renewable plant, low-cost, as a new biomass for the removal of mercury (Hg(II)) ions from aqueous solutions. The effects of various parameters like pH of solution, biomass concentration, contact time, and temperature were studied by the using the batch method. The Langmuir model adequately described the equilibrium data. The biosorption capacity of the biomass was found to be 107.4 mg · g^?1 at pH 6. The mean free energy value (10.9 kJ · mol^?1) obtained from the D–R model indicated that the biosorption of Hg(II) onto fungal biomass was taken place via chemical ion-exchange. Thermodynamic parameters showed that the biosorption of Hg(II) onto L. perlatum biomass was feasible, spontaneous, and exothermic in nature. The kinetic results showed that the biosorption of Hg(II) onto fungal biomass followed second-order kinetics. This work also shows that L. perlatum biomass can be an alternative to the expensive materials like ion exchange resins and activated carbon for the treatment of water and wastewater containing mercury ions due to its ability of selectivity and higher biosorption capacity and also being low cost material.     

Zinc (II) ion recovery by biosorption onto powdered waste sludge (PWS): effects of operating conditions

Powdered waste sludge (PWS) obtained from a paint industry wastewater treatment plant and pretreated with 1% H₂O₂ was used for biosorption of Zn(II) ions from aqueous solution. The effects of operating conditions, pH, temperature, agitation speed, PWS particle size, Zn ion and PWS concentrations on the extent of Zn ion biosorption were investigated in batch experiments. The optimum pH resulting in maximum Zn ion biosorption was found to be pH = 5, since Zn ions precipitated in the form of Zn(OH)₂ at pH levels above 5. The rate and extent of Zn ion biosorption increased with temperature between 25 and 50 °C, although biosorption was not strongly sensitive to temperature variations since the activation energy was low at 4.5 kcal mol^?1. Biosorbent particle size had a significant effect on Zn ion biosorption, yielding high percentage Zn removals at small particle sizes (D_p < 100 µm) or large surface areas of PWS. Agitation speed also considerably affected the extent of Zn ion removal, and should be above 150 rpm in order to obtain a high rate. The extent of Zn ion biosorption was also affected by the initial Zn ion and PWS concentrations. At constant biosorbent (PWS) concentration, percentage Zn ion removal decreased, but the biosorbed Zn concentration increased with increasing initial Zn ion concentrations. However, at constant initial Zn concentrations, percentage Zn removal increased, but the biosorbed Zn ion concentration decreased with increasing adsorbent (PWS) concentration. With a maximum Zn ion biosorption capacity of 168 mg g^?1 powdered waste sludge was proven to be an effective biosorbent compared to other biosorbents. Copyright © 2006 Society of Chemical Industry     

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.