膜技术在浓缩天然大豆低聚糖中的应用

应用膜分离技术特大豆分离蛋白的乳清进行低聚糖的回收、浓缩．结合实验结果,分析阐述了体系对超滤、纳滤、反渗透等浓缩过程的影响,并证明膜分离技术是回收利用大豆低聚糖经济有效的方法．     

纳滤提纯蔗果低聚糖实验研究和渗滤模型

用渗滤操作模式对蔗果低聚糖进行纳滤提纯，得到纯度在90％以上的蔗果低聚糖产品．结合渗滤数值模型，分析了膜对不同糖的截留性能；并将该模型运用于纯度与收率的分析．模型计算与实验结果的比较，证明渗滤模型对于蔗果低聚糖提纯具有较好的适用性．     

苯丙氨酸和天冬氨酸水溶液的纳滤分离及其过程模拟

选择苯丙氨酸和天冬氨酸水溶液进行了纳滤分离过程研究,讨论了不同pH下氨基酸的透过特性,并就该体系的浓缩分离进行了模拟计算。     

三醋酸纤维素正渗透膜用于大豆低聚糖浓缩的研究

<正>渗透(FO)过程是近些年发展起来的一种新型渗透驱动膜分离过程,它具有低能耗、高分离、低膜污染、常温常压下运行等优点,使其在诸多领域,特别在浓缩领域中有着很好的应用前景.通过相转化法制备三醋酸纤维素(CTA)正渗透膜,采用此正渗透膜对大豆低聚糖进行了浓缩,并研究了浓缩过程中膜的污染及清洗.结果表明,所制备CTA正渗透膜以去离子水为原料液,0.1mol/L NaCl为汲取液时的水通量为13.6L/(m2·h),对NaCl的截留率为94%~99%.在用于浓缩大豆低聚糖的过程中,累计浓缩150min,膜水通量由12.0L/(m2·h)降低到5.9L/(m2·h),总可溶物从1.0°Brix上升到8.0°Brix.在浓缩过程中正渗透膜表现出污染轻,易清洗等优点.     

染料水溶液纳滤脱盐和浓缩的过程模拟

分析了工业生产的NT染料水溶液的纳滤脱盐和浓缩过程中NaCl组分在膜液界面处浓差极化现象，将NaCl组分的传质系数与渗透流率关联起来，建立了适合于描述应用卷式纳滤膜作NT染料水溶液的纳滤脱盐和浓缩过程的简洁的模型方程。该模型的预测与实验结果具有良好的一致性，为应用纳滤技术进行相应的工艺预测和工种优化设计提供了新的方法。     

纳滤去除水中布洛芬的研究

分别从污染物的纳滤过程、溶液性质以及预接触时间等因素探讨纳滤膜去除环境微污染物布洛芬(IBU)的性能.结果表明,随着pH的增大布洛芬水溶液在纳滤过程中的通量也随之增大,布洛芬的离子化程度逐渐增大,其与膜面负电荷的互斥作用也增强,布洛芬溶液的纳滤过程持续保持较高的截留性能;加入天然有机物(NOM)后,布洛芬溶液膜通量明显降低,截留率值增大,膜面对IBU的吸附量降低;预接触时间的增大,对IBU的纳滤过程起始通量影响较大,膜面对IBU的累积吸附量变化并不大.     

纳滤浓缩绿茶提取液的研究和浓缩模型

研究了绿茶提取液的纳滤浓缩分离过程,采用两种操作方式:连续式浓缩和间歇式浓缩.在连续式浓缩实验中,通过测定不同操作压力下透过实验所得的通量、水脱除率和对茶多酚的截留率来分析纳滤过程的特点,在0.4~0.8 MPa下对茶多酚的平均截留率为97.3%.在间歇式浓缩实验中,测定了膜对不同茶水比浸取所得茶汤的截留性能,实验值与浓缩模型预测值进行了比较,实测值与模型值吻合较好,表明浓缩模型对于茶多酚的纳滤浓缩分离过程具有较好的适用性,可用于浓缩过程的设计计算.     

中性有机混合物溶液纳滤过程的实验考察

在实验考察温度、循环流速和葡萄糖浓度对葡萄糖溶质截留率的基础上,考察了纳滤过程中蔗糖与葡萄糖的浓度比对混合溶液溶质组分分离的影响.结果表明,在相同的渗透流率下,混合溶液中一组分的截留率因另一组分的存在而下降,渗透流率越大,体系越难分离;当渗透流率小于1.85×10-6m·s-1时,在考察的浓度比变化范围内,葡萄糖与蔗糖溶液的分离因子大于2.4.     

纳滤与反渗透膜处理含锰废水的初步研究

采用纳滤膜、反渗透膜分离技术对含锰废水进行了试验研究.考察了纳滤膜的操作压力、纯水/浓水比值、Mn2+浓缩倍数、Mn2+截留率及膜通量之间的关系.试验结果表明:纳滤膜对含锰废水有良好的处理效果,一级纳滤膜对Mn2+离子的平均截留率大于98％;浓缩倍数和膜通量随操作压力的升高而升高,2.0 MPa时,浓缩倍数可以达到8.2倍,膜通量可达到28～32 L/(m2·h).一级纳滤产生的纯水用反渗透膜进一步处理,反渗透膜对Mn2+离子的截留率在97％以上,纯水Mn2+离子浓度在0.5 mg/L以下,可以达标排放.     

高取代度氰乙基纤维素与二醋酸纤维素共混中空纤维纳滤膜的研制

采用高取代度氰乙基纤维素与二醋酸纤维素共混为膜材料,丙酮、二氧六环混合溶剂,以有机醇为主、加入适量其他添加剂为致孔剂,通过冰水凝胶浴干湿法纺丝,制得性能良好的中空纤维纳滤膜,该膜在给水质量浓度1 800 mg/L、操作压力为0.6 MPa、水温25℃条件下,对二价盐CaCl2、一价盐NaCl的水溶液的脱盐率分别大于90%和小于60%,水通量均大于3.5 mL/(cm2.h).还讨论了膜液的组成和纺丝条件对膜性能的影响.     

New processes for recovery of acetic acid from waste water

This paper addresses an industrially important problem of acetic acid recovery from a waste water stream via reactive distillation. The presence of a three-phase regime on the column stages due to a liquid–liquid phase split between aqueous and organic phases is a typical characteristic of this process. A modern modeling approach is presented to detect the existence of potential phase splitting in this column. A good agreement of a phase splitting model with the literature data has been shown. A theoretical study for the recovery of acetic acid from its 30 wt% aqueous solution by esterification with n-butanol is presented. Alternate column structures were investigated and two structures rendering theoretically close to 100% conversion of acetic acid were identified. The dynamic simulations were performed on proposed structures to see transient responses wrt. to common process disturbances. The work was originally presented at the PRES-2006 (27–31 August) conference in Prague, Czech Republic.     

Energy recovery from waste incineration: economic aspects

If we consider the desirability of reducing fossil fuel consumption, together with the increasing production of combustible solid wastes, there is clearly a need for waste treatment systems which achieve both volume reduction and energy recovery. Direct incineration method is one such system. The aim of this work was to analyze the municipal solid waste incineration situated in the Province of Turin (Piedmont, North Italy), especially its economical effects in consequence of the energy recovery that can be achieved. In order to perform this analysis, two kinds of energy recovery have been studied: electric energy (electrical configuration) only, and both electric and thermal energy (cogenerative configuration). So after a reconstruction of the economic situation, by considering all the costs and revenues, for both the possible energetic configurations the correspondence between the environmental convenience (that was evaluated in a previously work) and the economic convenience has been defined. The main obtained results highlight that currently the environmental convenience corresponds to the cogenerative configuration; instead the economical convenience in the actual condition corresponds to the only electric configuration. Anyway, by working on the thermal energy price, it is possible to obtain at the same time an environmental and economic convenience.     

Removal of excess fluoride from water using waste residue from alum manufacturing process

The ability of waste residue, generated from alum manufacturing process, to remove fluoride ion from water has been investigated. Series of batch adsorption experiments were carried out to assess parameters that influence the adsorption process. The factors investigated include the effect of contact time, adsorbent dose, thermal pretreatment of the adsorbent, neutralization of the adsorbent, initial fluoride concentration, pH of the solution and effect of co-existing anions. Results showed that Adsorption of fluoride is fairly rapid in first 5min and thereafter increases slowly to reach the equilibrium in about 1h. The removal efficiency of fluoride was increased with adsorbent dosage. About 85% removal efficiency was obtained within 1h at an optimum adsorbent dose of 16g/L for initial fluoride concentration of 10mg/L. Heat treatment and surface neutralization of the adsorbent did not improve the fluoride removal capacity and efficiency. The amount of fluoride adsorbed increased with increasing initial fluoride concentration. The percentage of fluoride removal remains nearly constant within the pH range of 3-8. The adsorption data at ambient pH were well fitted to the Dubinin-Radushkevick (D-R) isotherm model with a capacity of 332.5mg/g of the adsorbent. The adsorption kinetic was found to follow a pseudo-second-order rate equation with an average rate constant of 2.25gmin(-1)mg(-1). The presence of bicarbonate at higher concentrations (100-500mg/L) decreased the fluoride removal efficiency while other anions (chloride, sulfate, phosphate and nitrate) have no significant effect within the concentration range tested. The overall result shows that the waste residue is efficient defluoridating material.     

Metallurgical recovery of metals from electronic waste: a review

Waste electric and electronic equipment, or electronic waste, has been taken into consideration not only by the government but also by the public due to their hazardous material contents. In the detailed literature survey, value distributions for different electronic waste samples were calculated. It is showed that the major economic driver for recycling of electronic waste is from the recovery of precious metals. The state of the art in recovery of precious metals from electronic waste by pyrometallurgical processing, hydrometallurgical processing, and biometallurgical processing are highlighted in the paper. Pyrometallurgical processing has been a traditional technology for recovery of precious metals from waste electronic equipment. However, state-of-the-art smelters are highly depended on investments. Recent research on recovery of energy from PC waste gives an example for using plastics in this waste stream. It indicates that thermal processing provides a feasible approach for recovery of energy from electronic waste if a comprehensive emission control system is installed. In the last decade, attentions have been removed from pyrometallurgical process to hydrometallurgical process for recovery of metals from electronic waste. In the paper, hydrometallurgical processing techniques including cyanide leaching, halide leaching, thiourea leaching, and thiosulfate leaching of precious metals are detailed. In order to develop an environmentally friendly technique for recovery of precious metals from electronic scrap, a critical comparison of main leaching methods is analyzed for both economic feasibility and environmental impact. It is believed that biotechnology has been one of the most promising technologies in metallurgical processing. Bioleaching has been used for recovery of precious metals and copper from ores for many years. However, limited research was carried out on the bioleaching of metals from electronic waste. In the review, initial researches on the topic are presented. In addition, mechanisms and models of biosorption of precious metal ions from solutions are discussed.     

某大酒店废水热量回收分析

针对酒店蒸汽冷凝水大多未被利用的情况,定量分析不同条件下蒸汽凝结水利用方案,并进行节能计算和分析。     

Manganese recovery from secondary resources: a green process for carbothermal reduction and leaching of manganese bearing hazardous waste

During the hydrometallurgical extraction of zinc by electrowinning process, a hazardous solid waste called anode mud is generated. It contains large quantity of manganese oxides (55-80%) and lead dioxide (6-16%). Due to the presence of a large quantity of lead, the anode mud waste is considered hazardous and has to be disposed of in secure landfills, which is costly, wastes available manganese and valuable land resources. For recovery of manganese content of anode mud, a process comprising of carbothermal treatment using low density oil (LDO) followed by sulphuric acid leaching is developed.     

废水源热回收热泵使用前景分析

本文分析了废热水排放企业和公共浴室的给水和排水现状,.介绍了废水源热回收热泵的工作原理和特点,从不同角度分析了使用废水源热回收热泵的前景和重大意义.