应用超滤技术分析海藻酸钠对废水中Pb~(2+)的吸附规律

含铅离子废水污染事件近年来尤为严重,使得含铅废水的治理成为关系到社会稳定的重大环境安全问题之一。海藻酸钠为天然高分子有机物,来源广泛,成本低廉且无生物毒性,可吸附重金属离子形成凝胶。文章以超滤过程为研究对象,对海藻酸钠吸附Pb2+的的规律进行了研究,结论如下:(1)海藻酸钠对铅离子的吸附容量Q0随pH值的升高和铅离子的浓度升高而升高,吸附时间对海藻酸钠吸附铅离子的影响较小,在1分钟内就达到吸附平衡;(2)pH值对于铅离子的截留效果影响很大,pH值越高,铅离子的截留效果越好。     

海藻酸钠与聚乙烯醇包埋活性污泥强化聚酯废水生物处理

分别用海藻酸钠与聚乙烯醇（PVA）作为包埋剂包埋活性污泥，并添加活性炭作为添加剂，采用正交试验法．以聚酯废水COD的去除率为主要指标，小球强度和传质性能为辅助指标，确定了最佳包埋条件，将其应用于聚酯废水处理。研究结果表明，海藻酸钠小球COD去除率较普通活性污泥法提高了10％-20％，而聚乙烯醇小球则低于活性污泥法；且海藻酸钠小球传质性能也优于聚乙烯醇小球，但前者小球强度略低于后者。     

海藻酸纤维对铜离子的吸附性能

为了研究不同各类的海藻酸纤维对铜离子的吸附性能,用盐酸及硫酸钠水溶液处理海藻钙纤维,分别得到海藻及海藻酸钙钠纤维,把三种纤维分别与含铜离子的水溶液接触后,在不同的时间段测试溶液中铜离子的深度,结果表示：海藻酸、海藻酸钙及海藻酸钙钠纤维对铜均有较好的吸附性能,其平衡吸附容易分别为68.6mg/g,81.7mg/g和71.0mg/g,海藻酸钙纤维的吸附容量在三种纤维中最高,由于海藻酸钙钠纤维遇水后可以很快地吸水膨胀,其吸附速度较其它两种纤维快.     

海藻酸钠与钙或锌离子吸附平衡过程研究

使用原子吸收分光光度法测定了海藻酸钠对锌、钙离子的吸附平衡过程。试验结果表明,海藻酸钠对钙离子的结合能力较强,对锌离子的吸附容量较高。吸附平衡热力学数据表明海藻酸钙体系较为稳定;混合离子吸附的试验结果表明对钙、锌离子的选择性系数为1.35;钙锌离子交换试验表明钙离子与锌离子在海藻酸古洛糖醛酸片段的离子交换会影响锌离子与甘露糖醛酸片段的结合。     

生物吸附剂对废水中钙离子的去除试验

用活性污泥与沸石按一定比例配制成一种生物吸附剂,并在静态条件下,进行了生物吸附剂对废水中钙离子的去除试验和机理探讨。考察了生物吸附剂配方中活性基体用量、沸石用量及搅拌条件、溶液浓度、pH值等因素对钙离子去除效果的影响。结果表明:用生物吸附剂去除钙离子可以获得较好的效果,去除速度快,出水钙离子的质量浓度可降到200mg/L以下,满足工业循环水回用要求;去除机理可能有生物吸附、静电吸附、化学沉淀和离子交换;适当的剪切力可以加速吸附反应的进程,证实了流体力化学效应的存在。     

Removal of copper ions from aqueous solutions by adsorption onto wheat straw cellulose‐based polymeric composites

The wheat straw cellulose‐based hydrogels were synthesized by graft copolymerization followed by semi‐interpenetrating network technology. The prepared hydrogels were characterized through various methods including Fourier transform infrared spectra, scanning electron microscope, thermogravimetric analysis, and X‐ray photoelectron spectroscopy. Batch adsorption experiments were carried out to investigate the adsorption performances of hydrogels toward Cu(II) ions. The results suggested that the introduction of semi‐interpenetrating network polymers, sodium alginate and poly(vinyl alcohol), could greatly enhance the adsorption property of hydrogels. And the wheat straw cellulose‐g‐poly(potassium acrylate)/sodium alginate hydrogel showed a highest Cu(II) ions adsorption capacity of 130 mg/g. The equilibrium isotherm and adsorption kinetics were also studied. Besides, the mass transfer coefficients and the thermodynamics of Cu(II) ions adsorption were also probed. Finally, the X‐ray photoelectron spectroscopy analysis further demonstrated that the Cu(II) ions adsorption was mainly via complexation reaction of ? NH₂ and O‐containing groups in hydrogels. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46680.     

Synthesis and characterization of activated carbon and bioactive adsorbent produced from paper mill sludge

Adsorption capacity and bioactivity of a novel mesoporous activated carbon (IIT Carbon) and bioactive (BAC_IIT) catalyst produced from papermill sludge were evaluated. Conversion of paper mill sludge to useful activated carbons and biocatalysts is a significant process since it reduces environmental problems associated with disposal of waste sludge, enhances wastewater treatment using carbons produced from industrial waste itself, and promotes conservation of the naturally available primary resources currently used to make activated carbons. Analysis was conducted using synthetic wastewater containing phenol and a commercially available activated carbon, sorbonorite 4 (used as reference carbon). Phenol removal was accomplished in batch and fluidized bed reactors containing mesoporous activated carbon, sorbonorite 4, and the produced bioactive catalysts. Isotherm adsorption data indicated that mesoporous activated carbon has a higher adsorption capacity and molecular surface coverage than sorbonorite 4 for phenol concentrations less than 10 mg/l. The mass transfer limitation was accounted for the lower adsorption capacity of the microporous carbon (sorbonorite 4) in dilute solutions. The fluidized bed reactor study, however, indicated similar but slightly lower phenol removal capability for the produced mesoporous carbon. While phenol removal efficiency of the carbons studied was in the range 65–70%, the produced bioactive catalysts were able to remove up to 97% of phenol during first few hours of operation. These results suggest that mesoporous carbon will feasibly be a good substitute for other commercially available activated carbons produced from natural resources, not only in physical adsorption processes, but also in fluidized bed bioreactors (FBB), used in biodegradation processes.     

活性污泥对废水中铍的吸附与解吸

本文研究了活性污泥对水中铍的吸附特性。考察了时间、温度、pH、共存离子等对吸附过程的影响，以及吸附过程中溶液pH的变化规律，研究结果表明：铍在污泥上的吸附主要为快速的表面吸附，受温度影响不大，在pH3—7范围，吸附量随pH的升高而增大，铜、铅、锌、钙由于共同竞争吸附电位而使吸附量下降，铁、铝等由于产生微沉淀而致使吸附量增加，钠由于具有竞争和生成复盐双重作用导致吸附量交叉变化，硫酸根和磷酸根由于与铍生成沉淀而增加去除率，而氟和铍生成稳定配离子使去除率下降，溶液pH由于生成配离子而呈现反常的升高；此外，还探讨了不同解吸刑对污泥中铍的解吸效果，结果表明，盐酸解吸效果最佳，解吸率高达96．73％。     

Vanadium(V) Removal by Adsorption onto Activated Carbon Derived from Starch Industry Waste Sludge

This study examines the adsorption potential of activated carbons for vanadium (V) removal from aqueous solution. Activated carbons were produced via chemical activation of waste treatment sludge from the starch industry. Specific surface area and pore sizes of waste sludge samples were determined through chemical activation and pyrolysis. Experimental data indicated that sludge samples had micropore structure and specific surface area of up to 1196 m²/g. First-order and second-order models were applied to determine adsorption kinetics. Freundlich, Langmuir, and Dubinin–Radushkevich isotherms were used to analyze equilibrium data of adsorption. Equilibrium adsorption data showed the best fit to the Freundlich isotherm. Adsorption of vanadium (V) follows second-order kinetic models. Maximum adsorption was observed at pH 4.0. Langmuir adsorption capacity was found to be 37.17 mg/g. The results of the study indicated that activated carbon obtained from industrial sewage sludge was effective in removing vanadium from aqueous solutions, which creates a significant advantage for treatment of industrial wastewaters and management of solid wastes.     

Application of hydrogel for the removal of pollutant phenol in water

We prepared hybrid hydrogel of N-isopropyl acrylamide (NIPAM) and tributyl phosphate (TBP) for removing phenol by adsorption. The hybrid hydrogel was reinforced by thin layer coating of calcium alginate gel which was cross-linked by bivalent calcium ions. The prepared hybrid hydrogel was shown to effectively adsorb phenol from aqueous solution. The adsorption kinetic measurement showed that the thin layer coating of calcium alginate gel hardly hindered the mass transfer process of phenol. This is because of the superior hydrophilicity of calcium alginate gel which allows phenol molecules to diffuse in the hybrid hydrogel. The reinforced hybrid gel could be stripped of the adsorbed phenol with ammonia aqueous solution for multiple times. The thin layer coating of calcium alginate provided the hybrid hydrogel sufficient durability to carry out repeated cycles of adsorption and desorption.     

Cleaning Water Contaminated with Heavy Metal Ions Using Pyrolyzed Biochar Adsorbents

The extraction of pollutants from water using activated biochar materials is a low cost, sustainable approach for providing safe water in developing countries. The adsorption of copper ions, Cu(II), onto pyrolyzed and activated dried banana peel was studied and compared with the adsorption of copper ions onto a commercial activated carbon, F-400. Both the physical and chemical properties of the banana peel and activated carbon were measured. Pyrolysis of dried banana peels resulted in the formation of a large, porous surface area adsorbent with strongly negative surface charges.

Screening studies, which were designed to evaluate the effect of the mass of the adsorbent, pH of the solution, tumbling time, and initial Cu(II) concentration were conducted for each adsorbent. Equilibrium adsorption data were also analyzed, and the Freundlich isotherm resulted in a better fit than the Langmuir isotherm. The degree of favorability of adsorption of Cu(II) ions and adsorption capacity were 1.25 and 351.1 mg/g for pyrolyzed banana peel, respectively. The sorption kinetics fit a pseudo-second order equation. The mechanism of adsorption of metal ions on pyrolyzed banana peel followed ion exchange and electrostatic interactions resulting in the complexation of adsorbed ions.     

活化剩余污泥对含铅废水的处理正交实验研究

利用城市污水剩余污泥,采用ZnCl2与H2SO4对其进行活化,制得活化污泥,通过正交试验,考察了初始溶度、投加量、吸附时间与吸附温度对活化污泥对含铅废水的吸附效能影响。结果表面,含铅废水的初始溶度对活化污泥吸附废水的影响最大,其次是活化污泥投加量的影响,温度和时间对吸附的影响不大。在50 mL的水样中,其最佳吸附条件是,初始溶度0.1 mol/L,投加量0.4 g,去除率为73.87%。     

交联直写海藻酸盐水凝胶中空纤维的凝胶率与溶胀度

以海藻酸钠为原料、氯化钙为交联剂,反应直写制备海藻酸钙水凝胶中空纤维及组织工程支架.纤维的凝胶率和溶胀度直接影响支架的成形质量与所装载细胞的存活率.浸取分离所直写中空纤维的未交联部分,分析材料浓度对凝胶率的影响;以滴注凝固浴制备的海藻酸钙微球为对照组,分析直写工艺的溶胀度表现.结果表明,以4%海藻酸钠与3%氯化钙材料交联直写的中空纤维凝胶率和纤维形貌较好地满足了直写工艺的要求;随着海藻酸钠浓度的增加,中空纤维的溶胀度先减小后小幅升高并趋于稳定;随着氯化钙浓度的增加,凝胶纤维的溶胀度逐渐减小;反应直写工艺由于较小的两相接触表面,其溶胀度比凝固浴制备凝胶微球高2～5倍,更高的含水率有利于保障所装载细胞的活性和传质.     

Carbonaceous adsorbents from sewage sludge and their application in a combined activated sludge-powdered activated carbon (AS-PAC) treatment

In this study, waste biological sludge is converted to an adsorbent by chemical activation with sulphuric acid. The adsorbent obtained is then applied to the aerated vessel of an activated sludge process treating glucose and phenol to improve the quality of the treated effluent. The sludge-based carbonaceous adsorbent was found to be mesoporous in nature, with a good adsorption capacity for large molecular weight compounds and limited removal efficiency for smaller molecules such as phenol. The addition of carbon, either sludge-based or commercial, enhanced phenol removal from 58% to 98.7% and from 87% to 93% the organic matter removal as measured by the chemical oxygen demand (COD) when operated with feed concentrations of 100 mg phenol/l and 2500 mg COD/l. No differences were found between the activated sludge-activated carbon bench scale continuous reactors operating with either commercial or sludge-based adsorbents in spite of the higher adsorption capacity of the former. It is suggested that powdered adsorbent bioregeneration in the combined AS-PAC system may be impaired by the obstruction of pores due to bacterial growth, the effect being more important for the commercial activated carbon with a narrower pore size distribution.     

Removal of Hg2+ from aqueous solution using a novel composite carbon adsorbent

A novel composite carbon adsorbent (GCA) has been prepared by immobilizing activated carbon and genipin‐crosslinked chitosan into calcium alginate gel beads via entrapment and applied to the removal of mercury (Hg²⁺) ions from aqueous solution (e.g., drinking water). Two bead sizes and two mixing ratios of components were obtained and characterized. Batch experiments were performed to study the uptake equilibrium and kinetics of Hg²⁺ ions by the GCA. The Hg²⁺ adsorption capacity of GCA was found to be dependent of pH and independent of size of the adsorbent. The Hg²⁺ adsorption rate of GCA increases with decreasing its bead size. However, both adsorption capacity and rate of GCA for Hg²⁺ increase with increasing its chitosan content. Otherwise, it was shown that the GCA has higher Hg²⁺ adsorption capacity and rate than activated carbon, which might be caused by the incorporation of chitosan into the GCA. The maximum Hg²⁺ adsorption capacity of GCA was found to be 576 mg/g, which is over seven times higher than that of activated carbon. Our results reveal the uniform distribution of activated carbon and chitosan within the alginate gel bead and that Hg²⁺ ions can diffuse inside the bead. It also demonstrated the feasibility of using this GCA for Hg²⁺ removal at low pH values. The Hg²⁺ absorbed beads of the GCA can be effectively regenerated and reused using H₂SO₄. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

污泥活性炭处理亚甲基蓝染料废水的研究

采用污泥活性炭处理亚甲基蓝模拟染料废水,研究了模拟废水初始浓度、污泥活性炭投加量、pH值、水浴吸附时间等因素对染料废水的脱色率和COD去除率的影响,探讨污泥活性炭处理染料废水的适宜工艺条件。实验结果表明:随着染料废水初始浓度的增大,脱色率和COD去除率均表现出下降趋势;随着污泥活性炭投加量的增加,脱色率和COD去除率效果均十分明显;随着模拟废水pH值的增大,其脱色率基本呈现增大趋势,而COD去除率则先增大后减小,当pH在7.6～7.8时,脱色率与COD去除率均出现最大值;在延长水浴时间的同时,脱色率和COD去除率均表现出较好的效果。本实验处理染料废水的适宜条件为:染料废水的初始浓度为2.5mg/L,调节染料废水的pH值7~8,加入0.8g污泥活性炭,30℃条件下2h。     

Removal of heavy metals by polysaccharide: a review

ABSTRACT

Industries produce large amounts of heavy metal waste that are hazardous to the environment. Thus, heavy metal ions such as nickel (II), lead (II), copper (II), cadmium (II), and zinc (II), must be removed from wastewater. One commonly employed method is biosorption, which is the adsorption of metal ions by biomaterials such as polysaccharides. In this review, polysaccharides are classified into four groups: polysaccharide homopolymers, polysaccharide blends, copolymers, and polysaccharide composites. Pristine natural polysaccharides like chitin, chitosan, cellulose, starch, and alginate which have multiple functional groups. Additional functionalization is introduced in the form of blending, grafting, or mixing with various nanomaterials having additional functional group to make it more efficient for heavy metal ion adsorption. Introduction of second component onto the main polymer chain not only introduce functionality but enhance mechanical strength which is one of the vital requirements for the recyclability of adsorbent. Longer the time adsorbent is reused more economical is the removal process of metal ions from wastewater. Heavy metal ions undergo various types of interaction like π-π interactions, dipole–dipole interaction, hydrogen bonding or van der walls force with homopolymer, copolymers, blends, or nanocomposite having anions or electron-rich group. Adsorption process is studied by adsorption kinetics and adsorption isotherms. This review represents the adsorption behavior of chitosan, cellulose, starch, alginate, and their derivatives.     

Study to investigate the importance of mass transfer of naproxen sodium onto activated carbon

In the present study, the adsorption of naproxen sodium onto activated carbons (BK4, obtained from white polymeric waste and SK4, obtained from black polymeric waste) was investigated by calculating the parameters of pH, contact time, the concentration of naproxen sodium and the temperature. The adsorption data of naproxen sodium onto activated carbon follows the Langmuir isotherm model and its kinetic processes were described by various kinetic adsorption models. It was determined that the pseudo-second-order model was the best choice among all the available kinetic models to describe the adsorption behaviour of naproxen sodium onto activated carbon. During the present study, the intraparticle diffusion rate constant, the external mass transfer coefficient and the film and pore diffusion coefficient were evaluated at various temperatures. In addition, the thermodynamic parameters of the adsorption of naproxen sodium onto activated carbon were also calculated.     

响应曲面法优化木薯酒精污泥基活性炭制备及对没食子酸的吸附性能

以木薯酒精厂生产过程中产生的脱水污泥为原料,采用响应曲面法Box-Behnken模型优化了木薯酒精污泥基活性炭的制备工艺,同时对最优成品进行一系列表征分析,并将其应用于没食子酸废水的处理研究.活性炭的最优制备条件为活化温度489℃,浸渍时间14h,活化时间51 min,氯化锌浓度21.53％,该条件下样品的碘吸附值达5...     

固定化啤酒废酵母对Pb^2＋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Pb^2＋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Ph^2＋过程中的影响因素,包括初始Pb^2＋浓度、酵母菌体渡度、吸附时间和初始pH值等。试验结果表明,在初始Pb^2＋质量浓度为100mg／L、pH值为5、菌体酵母投加量为1.44g/L、吸附时间为180min的最佳条件下,固定化啤酒废酵母对Pb^2＋的吸附率为92.69％,吸附量为51.35mg／g,吸附符合Freunollich方程,相关系数R为0.99014。