活性氧化铝吸附法处理草甘膦生产废水的研究

研究了活性氧化铝处理草甘膦生产废水的工艺过程,得到了较适宜的吸附和脱附工艺条件。研究结果表明,活性氧化铝Al-1对该废水具有良好的吸附-脱附处理效果。在原废水中草甘膦质量浓度为10000mg/L．COD高达30000mg/L时,用10mL Al-1氧化铝吸附处理该废水(处理量为每批次100mL),革甘膦的去除率大于98%,COD去除率大于50%。     

电解铝废渣提锂方法研究

随着新能源汽车行业进入黄金发展期,动力锂电池行业呈爆发式增长,碳酸锂的需求量也逐年递增,含锂氟化盐的使用造成大量含锂电解铝废渣产生,如果得到合理回收利用,将有利于缓解新能源产业带来的用锂压力。重点研究了以含锂电解铝废渣和浓硫酸为原料,通过酸浸取等一系列工艺,制备电池级碳酸锂,同时副产冰晶石,并从实验原理、实验方法、工艺关键点控制、产品质量、工艺特点等方面进行了深度剖析。本工艺具有良好的社会效益、经济效益和环保效益,易于推广应用。     

Particulate composites from epoxy resin and fly-ash for the confinement of medium and low level radwastes

Water resistance of particulate fly-ash-epoxide composites, cured at low temperature by means of synthetic polyalkylenepolenepolyaminophenolic products, was tested at room temperature. Siliceous fly-ash (20% w/w) as filler reduces water penetration into the matrices, while saturation with water does not strongly affect the properties of the composites. The low value of the water diffusion coefficient through the material and the high mechanical properties of the particulate composites suggest further experimentation for its application in the confinement of low and medium activity nuclear wastes or of toxic chemical wastes.     

Treatment of DSD acid wastewater using a weak basic resin

The D301R resin was screened to separate DSD acid from DSD acid wastewater. The effect of pH, temperature and time on adsorption behavior was investigated. Batch experiments indicated that the COD removal ratio of DSD acid wastewater was over 86%, and the COD of treated wastewater was under 100 mg/L at appropriate operating conditions. The results of column dynamic adsorption and regeneration showed that COD could be efficiently removed by the D301R resin from DSD acid wastewater, and the resin was easily regenerated by NaOH stripping.     

生态化利用粉煤灰制备高纯超细氢氧化铝

采用矿物改性活化粉煤灰中Al2O3,消除阻止C2S晶相转变的干扰因素,实现了粉煤灰活化烧结料100%的自粉化,自粉化料平均粒径小于1μm;用质量分数为8%的碳酸钠溶液从活化粉煤灰中以NaAlO2形式提取铝组分,提取率大于75%;研究了表面活性剂种类与掺量、碳化速度、NaAlO2浓度、溶液pH值等因素对制备高纯超细Al(OH)3粉体的影响,找出了主要影响因素及最佳工艺参数,制备出了疏松无团聚的高纯超细Al(OH)3粉体,纯度大于99.9%,平均粒度小于200nm。     

吸附法去除废水中重金属研究进展

重金属污染问题已经成为近年来危害最大的水污染问题之一。各种有效去除水体中的重金属的处理技术与方法受到了世界各国政府和研究者们的极大关注。釆用吸附技术来处理含重金属的废水是一种非常有效和具有发展前景的方法之一。本文介绍了重金属水污染的现状与危害,废水处理中去除重金属常用的吸附剂。     

Characterization procedure for adsorption of DOC (Dissolved Organic Carbon) from synthetic wastewater

A characterization method to evaluate the composition of background organic matters in terms of adsorbability was presented and applied to synthetic and domestic wastewater. The binomial distribution of DOC (Dissolved Organic Carbon) fraction in relation of a characterizing variable, the Freundlich coefficient, k, was proposed to describe the initial composition of wastewater by a finite number of pseudospecies. This method was tested for removal of DOC by using granular and powdered activated carbons. These experiments enable us to get information on the distribution function of species in the solution. From the results obtained in this work, kinetic experimental data were predicted on the assumption that the diffusion coefficients were unchanged during the experiments. It was confirmed to be effective in determining the initial composition and describing the equilibria of the DOC. From the experiments, it was found that this synthetic solution has a sigmoid type isotherm on activated carbons. This implies that there are two different adsorption regions in a system, favourable and unfavourable cases, depending on the solution concentration. This unfamiliar problem can be solved by using a characterization method based on IAST-Freundlich model.     

The adsorption of dyes from aqueous solution using diatomite

Raw diatomite was calcined at 450 °C for dyes removal from aqueous solution. SEM and FTIR analysis show that the raw diatomite contains organic impurities, which are removed after the calcination. The impurities removal decreases the specific surface area and increases the average pore diameter of raw diatomite, while improves its adsorption capability of dyes. The adsorption isotherm and kinetics experiments of methylene blue onto calcined diatomite were then carried out to investigate the adsorption property. It shows that the adsorption capacity of methylene blue is about 50 mg/g. The adsorption isotherm was fitted by the Langmuir, Freundlich and Redlich-Peterson models, which reveals that the Redlich-Peterson isotherm is the best one. Two kinetic models, pseudo-first order and pseudo-second order, were rearranged for expediently investigating the adsortpion mechanisms. Fitting results show that the pseudo-first-order model is better in describing the adsorption process.     

Synthesis and adsorption property of zeolite FAU/LTA from lithium slag with utilization of mother liquid☆

Co-crystalline zeolite FAU/LTA-0 was synthesized by hydrothermal method from lithium slag. To make the most of excess silicon and alkali sources in mother liquid derived from FAU/LTA-0, zeolite FAU/LTA-1b was synthesized in the same method with the use of mother liquid by adding a certain amount of aluminum source. Influences of different adding ways of aluminum source and recycling dosages of mother liquid on synthesis of zeolites FAU/LTA with mother liquid were investigated. The phase, microstructure and thermostability of FAU/LTA-0 and FAU/LTA-1b were characterized by XRD, SEM and TG-DTA. The calcium and magnesium cation exchange capacities (CECs) of the zeolites were determined. The results have shown that co-crystalline zeolite can be synthesized with the use of mother liquid by adding aluminum source after 2 h of reaction. Compared with FAU/LTA-0, the crystal twinning structure of FAU/LTA-1b became weaker, the grain size was smaller, and the thermostability was better. With a lower dosage of mother liquid, the content of P-type impurity in product decreased significantly, and the content of LTA phase increased. The reuse rate of mother liquid can reach 48%. The CECs of FAU/LTA-1b-150 can reach 343 mg CaCO3·g?1 and 180 mg MgCO3·g?1, showing more excellent adsorption capacities than FAU/LTA-0 and commercial zeolite 4A. The full recycling use of mother liquid to synthesize zeolite FAU/LTA which can be applied for detergent not only improves resource utilization but also reduces production cost.     

Superior adsorption performance of graphitic carbon nitride nanosheets for both cationic and anionic heavy metals from wastewater

Water pollution caused by highly toxic Cd(II), Pb(II), and Cr(VI) is a serious problem. In the present work,a green and low-cost adsorbent of g-C_3N_4 nanosheets was developed with superior capacity for both cationic and anionic heavy metals. The adsorbent was easily fabricated through one-step calcination of guanidine hydrochloride with thickness less than 1.6 nm and specific surface area of 111.2 m~2·g~(-1). Kinetic and isotherm studies suggest that the adsorption is an endothermic chemisorption process, occurring on the energetically heterogeneous surface based on a hybrid mechanism of multilayer and monolayer adsorption. The tri-s-triazine units and surface N-containing groups of g-C_3N_4 nanosheets are proposed to be responsible for the adsorption process.Further study on pH demonstrates that electrostatic interaction plays an important role. The maximum adsorption capacity of Cd(II), Pb(II), and Cr(VI) on g-C_3N_4 nanosheets is 123.205 mg·g~(-1), 136.571 mg·g~(-1),and 684.451 mg·g~(-1), respectively. The better adsorption performance of the adsorbent than that of the recently reported nanomaterials and low-cost adsorbents proves its great application potential in the removal of heavy metal contaminants from wastewater. The present paper developed a promising adsorbent which will certainly find applications in wastewater treatment and also provides guiding significance in designing adsorption processes.     

Adsorption of pharmaceuticals from aqueous solutions on synthetic zeolites

The objectives of this study were to measure the sorption capacity of a dilute solution of drugs in water on hydrophobic zeolites and to quantify aspects of their adsorption mechanisms for potential use in wastewater remediation. The removal of three drugs, erythromycin (ERY), carbamazepine (CBZ) and levofloxacin (FLX) from water using three organophilic zeolites (Y, mordenite (MOR), ZSM-5) was investigated. Adsorption isotherms show that these three drugs are adsorbed in remarkable amounts by Y. These data were confirmed by thermogravimetric analysis. The presence of these drugs inside the Y cage was revealed by unit cell parameter variations and structural deformations obtained by X-ray structure analyses carried out using the Rietveld method on zeolite after adsorption. Our results indicate that the adsorption properties of zeolitic materials do not only depend on micropore size and that zeolite shape selectivity also depends on structural features which are difficult to determine “a priori”. In order to test the ability of organophilic zeolites in removing drugs from wastewater, the adsorption of ERY, FLX and CBZ on zeolite Y from water samples collected at the outlet of a wastewater treatment plant located in Northern Italy was determined. These drugs were almost completely adsorbed by Y zeolite, confirming that this material is suitable for removing drugs from wastewater.     

Utilization of waste cation exchange resin to prepare carbon/iron composites for the adsorption of contaminants in water

Carbon/iron composites were prepared from waste cation exchange resin by NaOH activation. The BET surface areas were over 1200 m² g⁻¹. The presence of iron led to the formation of new mesopores and macropores. Activation temperature had a significant impact on the pore size distributions, crystal structures, and magnetic properties of the carbon composites, and the magnetic properties of the composites were related to their crystal structures. The composite synthesized at 800 °C (800ACS-1) could effectively remove diethyl phthalate, bisphenol A, and malachite green from aqueous solutions. 800ACS-1 also exhibited high stability over a wide pH range of 4–11.5.     

Removal of copper (II) and phenol from aqueous solution using porous carbons derived from hydrothermal chars

The feasibility of hydrothermal char (HTC), a byproduct from biomass hydrothermal liquefaction for bio-oil production, as raw material for preparation of porous carbons was investigated in the present study. The resultant HTC-derived porous carbons were characterized and utilized as adsorbents for copper (II) and phenol removal from aqueous solution. Compared with porous carbons using pyrolytic char as precursor, the HTC-derived porous carbons exhibited unique textural features, e.g., narrow pore size distribution, high surface area and large pore size. In addition, FT-IR analysis confirmed that substantial amount of ketene groups existed on the surface of the HTC-derived porous carbons. As the adsorbents, the copper (II) adsorption onto HTC-derived carbons was strongly affected by the pH value of the solution in comparison with phenol adsorption. The carbons derived from pinewood and rice husk HTC exhibited high adsorption capacity of 83.88 and 39.30 mg/g for phenol and 25.18 and 22.62 mg/g for copper (II), respectively. The adsorption data for copper (II) and phenol onto the carbon adsorbents could be well described by Langmuir and Freundlich models. In comparison with pinewood sawdust HTC-derived carbon, the adsorption onto rice husk HTC-derived carbon preferentially followed Freundlich model due to the presence of silica on the surface.     

Preparation of molecular sieving carbon from waste resin by chemical vapor deposition

Molecular sieving carbons (MSCs) were prepared from carbonized phenol-formaldehyde resin wastes by the chemical vapor deposition (CVD) of the pyrolyzed carbon from hydrocarbon species. The pore size of the MSCs could be controlled in the range 0.37-0.42 nm by changing the hydrocarbon species pyrolyzed, the pyrolyzing temperature, and the processing time. It is shown that some of the MSCs have an excellent selectivity for separating CO₂ and CH₄, and others for separating C₃H₈ and C₃H₆. As the mechanism for controlling the pore size during CVD processing, we elucidated that the adsorption of hydrocarbon molecules first takes place on the pore surface and then the adsorbed hydrocarbons pyrolyze into carbon. Therefore, the pore size of the MSC can be adjusted by controlling the amount hydrocarbon adsorbed on the phenol-formaldehyde resin char.     

制备锂电池电解质六氟磷酸锂的工艺探讨

分析了目前国内外锂电池的发展状况,并对其中一种电解质六氟磷酸锂的制备工艺作了一些探讨。简要介绍了国外已经研究出的六氟磷酸锂的替代产品———氟烷基磷酸锂用作锂电池电解质。     

Modelling of adsorption of textile dyes over multi-walled carbon nanotubes: Equilibrium and kinetic

The paper deals with the application of multiwall carbon nanotubes (CNTs) to the adsorption of dyes from wastewater. Textile dyes are dangerous and diffused pollutant in wastewater, and the paper results confirmed the good adsorption ability of CNTs, with respect to classic active carbon, even for different dye types. The effect of surface treatments of CNTs was primarily investigated, revealing that neither the presence of residual catalyst nor common surface treatment (oxidation) affects the CNT's performances. Therefore less expensive nonpurified CNTs were assessed as good and economically convenient alternative for the process. In order to gain in generality in adsorption kinetic modelling, the parameters of the "best fitting" pseudo-second order model have been correlated to the main process variables (the dye initial concentration and the specific mass of CNTs.) setting-up a predictive kinetic model useful design new application of these materials in currently operating industrial operations for adsorption. In addition, isothermal data were used to screen all the relevant adsorption isotherms models and the Temkin model was confirmed as the more effective to accurately fit equilibrium data for any of the considered different dye types.     

吸附法在废水除磷中的应用

介绍了利用吸附原理在废水除磷中的研究进展,介绍了吸附材料的研究,包括天然矿物材料、工业废渣及其改性物、活性氧化铝及其改性物及其他多孔物质及人工合成的吸附剂等,并指出在实际应用中存在的问题。     

Removal of residual organic matter from secondary effluent by iron oxides adsorption

Residual organic matter (ROM) removal is an important issue in wastewater reclamation and reuse processes. Use of iron oxide particles (IOPs) as adsorbents for further treatment of the secondary effluent was investigated to mainly remove non-biodegradable residual organic matter under various operating conditions. ROM removal by IOP adsorption was evaluated in terms of the changes of UV absorbance, COD, and DOC concentrations in feed (secondary effluent) and treated water. The respective relationship of UV removal with COD and DOC removal efficiencies exhibited somewhat different profiles, possibly due to the influence of ROM properties on adsorptive removal mechanisms by IOP, such as hydrophobicity and coordinative capability. The types of IOPs such as ferrihydrite, geothite, and hematite were compared, and it was found that amorphous ferrihydrite was most effective in ROM removal. Maximum ROM removal was occuring at a solution pH of approximately 6.0, which might be ascribed to the ability of ligand exchange related to the association and dissociation of ROM molecules and IOPs at differing pH levels. Substantial reduction in the oxidation state (OS) of the treated water at high ROM removal indicated the coordination of highly oxidized groups in ROM at the IOP surface, such as carboxylic groups.     

煤矸石提铝提硅废液对烧结砖性能的影响研究

以煤矸石、粉煤灰和煤矸石提铝提硅废液为主要原料制备烧结砖,研究废液掺量对烧结砖抗压性能的影响。结果表明,不掺加废液时,烧结砖的最佳配方为:煤矸石80%,粉煤灰20%,水固比为15%,烧结砖的抗压强度为29.78 MPa;废液替代水的量为50%时,烧结砖的抗压强度为24.97 MPa,满足MU20等级的要求。     

PDMDAAC-膨润土对焦化废水的深度吸附处理研究

以聚二甲基二烯丙基氯化铵(PDMDAAC)和钠基膨润土为原料,制备了PDMDAAC-膨润土,发现PDMDAAC-膨润土对焦化废水具有较好的处理效果,PDMDAAC-膨润土在深度处理工业废水方面有广阔的前景。