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题名	高盐物料体系的纳滤脱盐应用基础研究
作者	罗建泉
学位类别	博士
答辩日期	2010-12-20
授予单位	中国科学院研究生院
导师	万印华
关键词	纳滤 高盐 脱盐 浓差极化 截留性能
其他题名	Fundamental Aspects in Desalination of Effluents with High Concentration of Salt through Nanofiltration Technology
学位专业	生物化工
中文摘要	纳滤（Nanofiltration, NF）膜是在20 世纪80 年代末期发展起来的一种新型分离膜，它的出现填补了超滤和反渗透之间的空白。纳滤膜已广泛应用于中低分子量物质的脱盐和纯化，但关于高盐浓度下的纳滤脱盐过程报道较少，对高盐环境下纳滤分离性能知之甚少。本文主要研究高盐对有机溶质的纳滤截留性能和浓差极化的影响，并将纳滤脱盐技术分别应用于中性溶质体系—右旋糖酐铁络合原液、带电溶质体系—亚氨基二乙酸酸化母液、混合溶质体系—酱油原液三种高盐工业料液的脱盐浓缩，对其工艺过程进行优化并开展中试放大试验。本文首先利用基于扩展Nernst-Planck方程的数学模型，评测了盐离子对纳滤膜和溶质的影响，并建立半经验模型预测高盐浓度对有机物的纳滤截留率的影响，分析了高浓度盐离子对纳滤膜以及溶质的影响机理，提出了高盐对纳滤过程的影响机理为：减小溶质半径、增加膜孔半径、增加有效膜厚，从而对实际工业物料的纳滤脱盐过程提供理论指导。将纳滤脱盐技术应用到右旋糖酐铁络合原液的脱盐过程，发现纳滤膜对右旋糖酐铁分子有优良的抗污染性，重点探讨了高浓度无机盐对纳滤浓差极化的影响，证明了盐离子会增加物料的粘度从而加重浓差极化的机理，并优化工艺以控制高盐高粘度物料纳滤脱盐过程中的通量衰减。最后进行了右旋糖酐铁络合原液的纳滤脱盐浓缩中试试验，将络合原液中的盐浓度从18%wt降至2%wt以下，同时将右旋糖酐铁浓度提高至原来的3倍。将纳滤脱盐技术应用到亚氨基二乙酸（IDA）酸化母液的脱盐过程，重点探讨了工艺参数对IDA纳滤截留性能的影响，发现NF270纳滤膜对IDA的表观截留率大于90%。优化了操作模式，采用浓缩-渗滤相结合的模式，脱盐率为58.4%时IDA回收率达95.8%。进行了初步的中试试验，提出了IDA酸化母液纳滤脱盐循环套用新工艺。将纳滤脱盐技术应用到酱油原液的脱盐和脱色过程，通过两步纳滤法分别获得了低盐酱油和浅色酱油，所得低盐酱油达到国家特级酱油标准（氨基酸态氮≥8.0 gL-1，可溶性无盐固形物≥150 gL-1）。重点研究了酱油纳滤脱盐的操作方式优化，建立了稀释-浓缩-渗滤模型用以预测截留液的溶质浓度或者耗水量，分析了膜污染规律并探讨了酱油污染清洗方法。完成现场中试试验，建立了将酱油原液稀释2倍后一步浓缩至合格产品的简单操作策略，并寻找到合适的食品级复合清洗剂，实现了纳滤膜的高效再生。
英文摘要	As a new separation membrane technology developed in the late 1980’s, nanofiltration (NF), a pressure driven process, becomes the transition between ultrafiltration and reverse osmosis. NF membranes can be used for desalting and purifying the low molecular weight substances, but very few results concerning NF of concentrated salt solution have been reported and the knowledge about NF performances under highly concentrated salt is rare. This paper is to introduce the effect of highly concentrated salt on retention of organic solutes and concentration polarization in NF processes. Moreover, NF desalination has been applied to three industrial effluents with very highly concentrated salt (dextran iron complex, iminodiacetic acid mother liquor, raw soy sauce), and these processes have been optimized and pilot-plant tests also have been carried out. Based on extended Nernst-Planck equation, effect of salt ions on NF membranes and solutes was examined, and a semi-empirical model was proposed to predict retentions of organic solutes in highly saline solution. Effect mechanism of highly concentrated salt on NF and solutes was discussed from three parts: decreasing solutes size, increasing membrane pore size, and increasing effective membrane thickness. These results could serve as a valuable guide for NF-desalination process of industrial feeds. NF-desalination was applied for desalination of dextran iron solution (neutral solutes system), and NF membranes used in this study showed an excellent anti-fouling performance for the iron dextran molecules. Effect of highly concentrated salt on concentration polarization in NF was discussed seriously, showing that, salt ions would increase concentration polarization by enhancing viscosity of feed. Process optimization was carried out to control flux decline during NF-desalination of feed with highly concentrated salt and high viscosity. Then, a pilot-plant study was performed successfully, and the salt concentration in solution decreased from 18%wt to <2%wt, while dextran iron was concentrated by three times through NF technology. NF-desalination was applied for desalination of IDA mother liquor (charged solutes system), and effect of process parameters on retention of IDA by NF was studied, showing that the observed rejection of IDA by NF270 was more than 90%. Operation mode was optimized, and with combined mode of concentration and diafiltration, the recovery of IDA was about 95.8%, NaCl removal was 58.4%. Preliminary pilot-plant tests were carried out and a process route that the desalted mother liquor was recycled by NF in IDA production was proposed. NF-desalination was applied for desalination and decolorization of raw soy sauce (mixed solutes system), and low-salt soy sauce and light-color soy sauce were obtained separately. This low-salt soy sauce met Super Class Quality Standards defined in China National Standards (amino nitrogen ≥ 8.0 gL-1, soluble solids excluding sodium chloride ≥ 150 gL-1). Optimization of operation mode was performed and a model of dilution-concentration-diafiltration was established to predict solutes concentration in retentate or water consumption. Membrane fouling and cleaning in NF of soy sauce were analyzed, and pilot-plant tests were carried out successfully and a simple operation mode that two-fold diluted soy sauce was concentrated to eligible products was established. At a low concentration for a short duration, the composite cleaning agent containing alkali, surfactant and enzyme could completely recover the flux of severely fouled membrane.
语种	中文
公开日期	2013-09-22
页码	154
内容类型	学位论文
源URL	[http://ir.ipe.ac.cn/handle/122111/1633]
专题	过程工程研究所_研究所（批量导入）
推荐引用方式 GB/T 7714	罗建泉. 高盐物料体系的纳滤脱盐应用基础研究[D]. 中国科学院研究生院. 2010.

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