木质纤维素生物质磁性炭的水处理应用进展

生物质炭材料因独特的孔道结构与优良的吸附性能引起广泛关注,如何有效提升其吸附效率并与水相快速分离仍是极具挑战的问题。该文从磁性纳米颗粒的合成方法出发,综述了木质纤维素生物质磁性炭复合材料的制备方法,对比分析了致孔方法、浸渍比率、炭化温度、炭化时间、炭化方式等因素对其孔道结构的影响,进而介绍了其在水处理领域的应用研究、吸附机制及重复利用情况,最后针对木质纤维素生物质磁性炭材料现阶段所面临的挑战,提出今后的研究重点与方向。     

生物质炭可控制备及在水处理中的应用

综述了近年来常用的农业废弃物、污泥、植物以及生物高聚物生物质炭在水处理中吸附污染物的研究与应用。不同的原料、热解温度和热解时间会导致生物质炭的产量、元素组成以及理化性质有所不同,可根据吸附质的特性合成生物质炭。在今后的研究过程中,一方面应尝试成本效益好的规模化生产,另一方面应加强对生物质炭的长期吸附效应的研究。     

木质纤维素类生物质水热炭化机理及水热炭应用进展

通过水热炭化方法 （HTC）制备纤维类生物质炭材料,是当前废弃生物质高值化处理的一种方式。生物质具有种类繁多、结构复杂的特点,在不同的水热条件下涉及水解、降解、聚合等复杂反应。制备的水热炭性质如形貌、孔结构、表面官能团分布等受原料物理化学结构和水热反应条件影响较大,而水热炭的性质直接影响水热炭的应用。木质素炭化需要较高的水热强度,生成的水热炭石墨化程度和稳定性更高,可应用于导电、耐高温材料等领域;纤维素、半纤维素相对于木质素炭化温度低,更易形成多孔结构,获得更高的比表面积。另外二者因富含羟基,制备的水热炭表面具有丰富的含氧官能团,有利于通过静电吸附、离子交换等过程实现污染物吸附,进一步应用于环境治理等领域。水热温度主要影响炭化程度和水热炭得率,而水热时间则对水热炭形貌具有更明显的作用。通过改性可以定向调控水热炭性能,扩大其应用领域范围。为明晰不同条件下水热炭的结构变化,本文综述了纤维类生物质的种类、原料组成及水热条件对水热炭结构的影响,深入分析了水热炭生成机理,探讨了生物炭改性方法,归纳了生物炭在不同领域的应用并展望了未来的发展方向和前景,为生物质基水热炭研究提供参考。     

生物质炭在废水处理中的应用进展

生物质炭具有原料来源广泛、制备工艺简单、表面和结构性能优良等优点。本文综述了生物质炭在废水处理中的最新进展,介绍了基于不同侧重点的生物质炭改性方法,总结了生物质炭去除重金属、无机污染物等废水的机制,并提出了对生物质炭未来发展的思考,为生物质炭的研究和应用提供参考。     

磁性生物质炭的制备及在污染水体中的应用

介绍了磁性生物质炭的制备方法及所需的原料,尤其是在污染水体中的应用。阐述了磁性生物质炭的制备方法,包括浸渍-热解法、液相还原法、共沉淀法和物理混合法,并指出各种制备方法的优缺点。重点分析了磁性生物质炭吸附污染物的影响因素及机理,发现磁性生物质炭的热解温度及投加量、溶液的pH、反应时间、污染物的初始浓度、吸附温度和溶液中其他竞争离子等对污染物吸附效果都有一定的影响,而且其吸附机理比较复杂,关键的吸附机理包括物理吸附、离子交换、静电吸附、共沉淀、表面络合等。详细总结磁性生物质炭在污染水体中的应用,磁性生物质炭已广泛用于去除水体中的各种污染物,包括重金属、无机阴离子、抗生素、农药、有机染料及核污染物。此外,还对磁性生物质炭的再生和回收进行了评价。     

改性生物质炭去除水中污染物的研究进展

简述了生物质炭的改性方法 (蒸汽活化、酸改性、碱改性、浸渍法),并对改性过程机理进行分析,总结了改性生物质炭对水中重金属、阴离子、有机污染物的去除效果。在此基础上,对未来的研究方向进行展望,认为生物质炭的再生处理是研究重点之一,结合其他功能材料形成新的复合水处理材料也是今后的研究重点。     

生物质炭钝化土壤重金属的研究进展

针对生物质炭存有的基本性质、修复土壤重金属污染的主要影响因素以及改性生物质炭对土壤重金属生物有效性的影响进行了客观分析,并结合国内外当前在生物质炭钝化土壤重金属方面的研究现状,以期能为我国土壤重金属的进一步合理处理和提高生物质炭钝化效能提供一定的参考。     

沼渣生物炭在水处理中的应用进展

以沼渣为原料制备生物炭是实现沼渣安全处置和资源化利用的有效途径之一.沼渣经过厌氧消化处理,在一定程度上优化了沼渣生物炭的组分结构和物化特性,因而沼渣生物炭具有低成本、来源广、吸附及催化性能好等特点被应用于去除水中污染物.该文对当前沼渣生物炭的原料来源、制备及改性方法进行了总结,归纳了沼渣生物炭作为吸附剂和碳基催化剂在水...     

废物资源化制备生物质炭及其应用的研究进展

生物质炭作为一种多功能性材料正逐步受到人们的广泛关注。本文综述了以废弃物为原料制备生物质炭,给出了制备生物质炭的主要工艺,并对生物质炭的主要物理化学性质如元素组成、碱度、表面特性和孔隙结构进行了介绍。然后对生物质炭在农业和环境领域中的应用做了相应介绍,例如用作土壤改良剂提高土壤肥力、增加碳固定、减少温室气体排放,作为一种高效吸附剂同时去处污水中重金属及有机污染物等。最后,对今后生物质炭的研究方向作出了展望,指出应继续研究尽快实现生物质炭的大量、高效、廉价生产,从原料和工艺方面着手进一步提高生物质炭的比表面积,使其成为活性炭的替代品,同时进一步研究对土壤的改良和修复、对农作物生长和产量的促进以及对温室气体的减排作用的机理,并提供大面积的长期的实验数据支持。     

生物质炭在重金属污染土壤修复中的应用研究现状

为充分发挥生物质炭多孔性、表面活性、选择性吸附和高碱性等性能在有效控制重金属生物迁移中的作用,以期为重金属污染土壤修复技术提供参考。介绍了我国重金属污染土壤的概况,综述了生物质炭在重金属污染土壤修复中的应用,重点介绍了植物修复、化学淋洗、土壤性能改良、固化/稳定化、热解吸修复和电动力学修复等技术的应用情况,简要概述了原料种类、热解温度和表面官能团对生物质炭性质及生物质炭对土壤环境的影响,并展望了生物质炭在重金属污染土壤修复中的发展前景。     

饮水中有机污染物的危害及对策

饮水有机污染是现代社会面临的严峻挑战，日益污染的水质对人类健康造成极大威胁。提高饮水的有机污染物控制指标及水处理管理水平，并在常规给水处理工艺的基础上进行有效的深度处理，有着重要的现实意义。     

Effects of static magnetic field on water at kinetic condition

Water was exposed for different times to weak static magnetic field (MF) generated from a stack of magnets (B = 15 mT) or from a single permanent magnet (B = 0.27 T) at flow conditions. The water conductivity and the amount of evaporated water were measured as a function of time following the application of MF. It was found that the MF decreases the water conductivity, which is inversely proportional to the flow rate, and increases the amount of evaporated water, even after the water's distillation. The effects are due to the hydrogen bond network strengthening and the perturbation of gas/liquid interface from the air nanobubbles in the water.     

Organic matter removal in boiler feed water treatment of a power plant with ozone

The purpose of this work was to test the effectiveness of ozone as a treatment to remove organic matter of the boiler feed water of a power plant. In the experiments carried out in the power plant Endesa in As Pontes (Spain), chlorine was substituted for ozone in the pre‐treatment stage. The use of ozone reduced the organic content of the boiler feed water by an average 20% compared with chlorination and by 50% when ozone was combined with hydrogen peroxide. The latter treatment achieved an organic content in the boiler feed water of less than 40 μg C/L. The ozone treatment also reduced the content of trihalomethanes in the drinking water, produced by the same plant, to values in the range of 10 μg/L and even to undetectable values when ozone was combined with hydrogen peroxide, in spite of the postchlorination applied to this stream to ensure a disinfectant capacity though the distribution system.     

膨润土改性产品在废水处理中的应用及进展

本文介绍了膨润土基本的矿物学性质,阐述了膨润土及其改性产品在废水处理中的有效作用及应用前景。膨润土经改性后可用于处理多种工业废水,其中对染料废水、重金属离子废水和有机废水,其去除率比原土高。同时,对膨润土的发展应用问题进行了展望。     

Designed multifunctionalized magnetic mesoporous microsphere for sequential sorption of organic and inorganic pollutants

A novel magnetic microsphere with thiol-functionalized mesoporous shell was fabricated by using a colloidal chemical method and cationic surfactants (CTAB) as structure-directing agents. As a high performance adsorbent, these microspheres were examined for environmental protection applications to adsorb and remove toxic phenolic compounds and heavy metal ions, sequentially, in aqueous solution. The prepared nanocomposite microspheres were mesoporous and magnetizable, with a diameter of 350-400 nm, a high surface area of 913.14 m²/g, a pore size of 2.48 nm, and a saturation magnetization of 33.9 emu/g. These multifunctional microspheres showed excellent adsorptive capability towards toxic phenolic compounds and heavy metal ions (Hg²⁺, Pb²⁺). The cation micelle made of CTAB in the mesopores has great attractive power to phenolic compounds and the adsorption capacity was as high as 144.78 mg/g for 4-methyl-2,6-dinitrophenol. The thiol-functionalized magnetic mesoporous microsphere (TMMM) which had adsorbed phenolic compounds can further adsorb metal ions after removing CTAB. The adsorption capacity was 185.19 mg/g for Hg²⁺ and 114.7 mg/g for Pb²⁺. The TMMM can be easily removed from solution by an external magnetic field. These results suggest that this kind of nanocomposites is potentially useful materials for effectively adsorbing and removing different dangerous pollutants in aqueous solution.     

The remediation of MTE water by combined anaerobic digestion and chemical treatment

Mechanical thermal expression (MTE) is a developing process for the non-evaporative removal of water from low-rank coals prior to combustion. The water removed in this process contains both organic and inorganic components that would prevent its direct disposal to the environment. This study investigated the use of anaerobic digestion, in combination with ozonation and/or coagulation, to remediate MTE water.Under appropriate conditions the concentration of organic impurities, as determined by BOD, was reduced to be below guideline limits for release to surface waters. However, the electrical conductivity was increased to levels that would only permit its use for irrigation of salt tolerant plants with adequate drainage.Evidence of the effectiveness of remediation for organic carbon removal was also demonstrated by FTIR and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS). The latter revealed that the volatilizable organic components (aliphatic and aromatic hydrocarbons) were reduced by ∼95% by anaerobic treatment.     

Synthesis and characterization of polymeric inorganic coagulants for water treatment

This research explored the feasibility of preparing and utilizing preformed polymeric solution of Al(III) and Fe(III) as coagulants for water treatment. The differentiation and quantification of hydrolytic Al and Fe species in the coagulants were done by utilizing spectrophotometric method based on the interaction of Al or Fe with ferron as a complexing agent. In addition, 27A1-NMR, FT-IR, and powdered XRD were used to characterize the nature and structure of the hydrolytic species in these coagulants. The properties of the polyaluminum chloride (PAC1) and polymeric iron chloride (PIG) showed that the mass fractions of the maximum polymeric Al produced at r(OH/Al)=2.2 and Fe at r=1.5(OH/Fe) were 85% and 20% of the total aluminum and iron in solution, respectively. Coagulation tests were conducted under various coagulant dosages and pHs for each coagulant prepared. In case of PAC1 coagulants, a coagulation test on Nakdong river waters with three PACls (r=2.0, 2.2, 2.35) showed that the effectiveness of coagulation was in the order, r=2.2>2.0>2.35, corresponding to the order of polymeric aluminum contents. And, for the PIC1 coagulants, the PIC1 of r=1.5 was most effective for the removal of turbidity and TOC from the raw water. Presented at the Int’l Symp. on Chem. Eng. (Cheju, Feb. 8–10, 2001), dedicated to Prof. H. S. Chun on the occasion of his retirement from Korea University.     

Effect of pH on the rejection of inorganic salts and organic compound using nanofiltration membrane

Nanofiltration (NF) has recently received increased attention as a possible tertiary treatment process providing high rejection of solutes and high water flux rate. In this research, solute separation experiments using NF membranes were made with inorganic salts including heavy metal and organic compounds in different pH levels. The rejection of inorganics from feed solution was found to be dependent on the electric charge of membrane as well as the ionic radius and valence of ion. The divalent cation appeared to reduce the potential of negatively charged membrane to lower the rejection of ion. The results of organic compounds showed that the rejection could be estimated from the pKa value and molecular weight of organics, and the pH of the feed solution.     

A typical application of magnetic field inwastewater treatment with fluidized bed biofilm reactor

The effects of a magnetic field on wastewater treatment with a fluidized bed biofilm reactor was investigated. With glucose being the sole carbon source, the activated sludge obtained from a real wastewater treatment plant was used as a seed. Magnetically loaded polystyrene beads at the size of 500-595 w m were used as support materials for biofilm formation in a fluidized bed biofilm reactor. Magnetic field application allowed the operation of the column at high liquid flow rates, thus external diffusion limitations on the biofilm surface were lowered and the efficiency of biodegradation was increased. Denser, thinner, and more active biofilm was obtained with magnetic field application, especially in pulsed form. As expected, the system performance changed with operational parameters, and the increase in substrate removal reached up to 26% with pulsed application of a 17.8 mT DC-magnetic field under optimum conditions.