Application of response surface methodology to optimize the operation process for regeneration of acid and base using bipolar membrane electrodialysis

BACKGROUND: Bipolar membrane electrodialysis (BMED) has been widely used for desalination, concentration, separation, and purification in many fields. The purpose of this study is to optimize the operation conditions using response surface methodology (RSM) for the regeneration of sulfuric acid and ammonia from ammonium sulfate solution by BMED coupled with ammonia in situ stripping. RESULTS: A three‐factor central composite design of RSM was used to analyze the effect of operation conditions (current density, flow rate, initial acid concentration) on average current efficiency (ACE) and establish the optimal operation conditions. The ACE was 76.7 ± 2.2% under optimal operation conditions (current density 23.8 mA cm^?2, flow rate 27.3 L h^?1, initial acid concentration 0.09 mol L^?1). CONCLUSION: A suitable regression model for predicting ACE within the ranges of variables used was developed based on experimental results. The operation conditions were optimized by RSM and the ACE obtained under the optimal operation conditions was in good agreement with the value predicted by the regression model (78%), which proved the validity of the model. Copyright © 2007 Society of Chemical Industry     

Effect of Process Parameters on Separation Performance of Nitrate by Electrodialysis

Abstract

The electrodialytic separation of nitrate from water was investigated as a function of feed characteristics such as applied voltage, feed flow rate, and nitrate concentration in the solution. The separation performance was evaluated in terms of percent removal of nitrate, process time, and energy consumptions. TS‐1‐10 electrodialysis equipment (Tokuyama) was used in experimental studies. During the unsteady state run of the ED system, both inlet and outlet concentrations of nitrate and conductivities of streams were measured at certain time intervals until the current drops to 0.01 A. It was obtained that the percent removal of nitrate from the solution increased when the concentration of nitrate in the feed solution increased. The operation time became shorter when a high potential was applied.     

含钒灰渣酸浸液结晶铵明矾的工艺条件

为获得含钒灰渣酸浸液结晶铵明矾的优化工艺条件,利用正交优选法研究了Al2(SO4)3浓度、铵/铝摩尔比、冷却速度和结晶温度对铵明矾结晶率的影响,分析了铵明矾晶体和滤液的成分,计算得到了铵明矾的结晶率. 结果表明,4种因素对铵明矾结晶率均有较大影响,Al2(SO4)3浓度、铵/铝摩尔比对铵明矾结晶率影响较为显著. 合理的铵明矾结晶工艺条件为：Al2(SO4)3浓度150~200g/L,铵/铝摩尔比1.2左右,冷却速度15℃/h左右,结晶温度5℃左右. 在此条件下,铵明矾结晶率为89.32%.     

Removal of zinc ions in wastewater by electrodialysis

To obtain useful data for treatment of the wastewater discharged from zinc electroplating processes, we investigated the effects of operating parameters, such as the initial concentration of dilute solution, the flow velocity and the applied voltage, on removal rate of Zn²⁺ in the model solutions using an electrodialysis system. Zinc ions in the solutions were effectively removed by the electrodialyzer with CMX cation exchange membranes and AMX anion exchange membranes. The initial concentration of dilute solution, the flow velocity and the applied voltage strongly affected the performance of the electrodialysis system. As the initial concentration of dilute solution, the flow velocity and the applied voltage were increased, the removal ratio was increased. The energy consumption was increased as the initial concentration of dilute solution and the applied voltage were increased, whereas the effect of the flow velocity on the energy consumption was negligible.     

Separation of copper ions by electrodialysis using Taguchi experimental design

With the aid of atomic absorption, a systematical and analytical evaluation method called Taguchi's quality engineering has been applied for the separation of copper ions from a solution using a laboratory electrodialysis set-up to evaluate the optimal experimental conditions and hence to achieve the highest removal percentage and the best robustness of the quantitation from the least number ofexperimental runs. Fourparameters at three levels were studied: concentration (100, 500, 1000 ppm), temperature (25, 40, 60°C), flow rate (0.07, 0.7, 1.2 mL/s) and voltage (10, 20, 30 V). Two types of different membranes with different ion-exchange capacities were used. The optimal levels thus determined for the four influential factors were: concentration 1000 ppm, temperature 60°C, flow rate 0.07 mL/s and voltage 30 V. It has also been found that using a membrane pair with higher ion-exchange capacity improves performance. The highest removal percentage was found to be 94.94% and 97.33% for the two types of membranes.     

谷氨酸发酵废水电渗析脱盐

采用普通电渗析脱除谷氨酸发酵废水中的无机盐,用活性炭对废水进行预处理,考察了预处理前后废水的电渗析性能. 结果表明,活性炭用量为100和200 g/L时,在60℃下处理30 min,废水的脱色率分别达61%和75%. 预处理前及100和200 g/L活性炭预处理后乳酸迁移量依次降低,谷氨酸迁移率分别为24%, 35%和39%, SO42-迁移率分别为77%, 80%和84%, NH4+迁移率分别为89%, 86%和84%,膜堆电阻依次增加,SO42-脱除率达85%时,能耗分别为4.88, 3.93和3.64 kW×h/kg.     

电渗析法处理丙烯腈废水的研究

为了去除丙烯腈废水中的硫酸铵,采用电渗析法对丙烯腈废水进行脱盐处理。脱盐率随流量的升高而降低,随电压的升高而升高,但达到一定值后,脱盐率基本不随电压的变化而变化。流量升高,能耗降低;电压越高,能耗越高。在电压为10V、流量为50L/h的条件下,具有较好的电渗析效果,能耗在16.81kJ/g左右,温度提高有利于电渗析过程的进行。实验结果表明,该法切实可行。     

硫酸铝铵-氯化氢反应制备六水氯化铝过程中晶体形貌的研究

以十二水合硫酸铝铵为原料,采用氯化氢通气结晶法制备了六水氯化铝晶体,考察了通气速率、通气时间、反应温度、铝离子初始浓度对六水氯化铝晶体形貌的影响。结果表明,50 mL硫酸铝铵酸溶液中,当通气速率为60 mL/min、通气时间为2 h、反应温度为30 ℃、铝离子初始质量浓度为20 g/L时,可以得到形貌比较规整的棱柱形六水氯化铝晶体。该研究为提取、制备高品质六水氯化铝晶体提供了技术参考。     

高效脱除结晶硫酸铜中杂质钙的研究

基于相分离原理,文章研究了从硫酸铜废液中高效除钙的方法.通过加入无水硫酸钙晶种,将硫酸铜溶液或含硫酸等其他组分的硫酸铜溶液在蒸发浓缩阶段除钙,蒸发浓缩后,趁热过滤将固体硫酸钙与硫酸铜溶液分离.具体工艺条件：蒸发浓缩阶段温度80～105度,搅拌时间5小时,无水硫酸钙晶种加入量1～15克/升,即可通过一次浓缩结晶过程,可使所得五水硫酸铜产品钙含量降到0.005 wt.％以下.     

电渗析法处理污染三甘醇工艺优化研究

以长庆靖边气田被污染的三甘醇溶液为实验对象,采用四室电渗析反应器对其进行净化处理,研究了操作电压、运行时间、淡室进液流量、进液总溶解性固体(TDS)浓度等因素对处理后溶液品质的影响。在单因素实验的基础上,采用响应面分析法对电渗析工艺进行了优化。优化的工艺条件为:操作电压48.92 V,运行时间128.09 min,淡室进液流量12.00 L/h,当被污染的三甘醇溶液TDS质量浓度为1 968 mg/L时,在此工艺条件下处理后TDS浓度可降至(38.3±1.2)mg/L。实验中对电渗析过程的极限电流进行了测定,在淡室进液流量为12.00 L/h时,测得极限电流为0.189 A,对应的极限电压为66 V,说明装置在优化条件下运行不会出现浓差极化等不正常现象。     

铝材表面化学镀镍技术

在常规铝材化学镀镍工艺基础上，提出一种在酸性化学镀镍前增加一道碱性化学预镀镍工艺的铝材表面化学镀镍新技术。介绍了其预镀镍的工艺流程与操作要点。研制了一种中等浓度的含镍、铁的多元合金浸锌液，并通过正交实验得出了浸锌最佳方案，确定了碱性化学预镀镍的最佳配方：25g／L硫酸镍，25g/L次磷酸钠，30g／L柠檬酸三钠，10g／L焦磷酸钠，10-15mL／L三乙醇胺，30g/L氯化铵。弯曲试验表明，镀镍层与铝基体结合强度很高；镀镍层SEM照片显示，镀镍层晶粒尺寸大小均匀，各晶粒间结合紧密，孔隙率低，耐腐蚀能力强。     

Study on Riboflavin Recovery from Wastewater by a Batch Foam Separation Process

Abstract

A batch recovery of riboflavin via foam separation from industrial simulative wastewater was studied using a cationic surfactant, cetyltrimethyl ammonium bromide (CTAB). The experimental parameters examined were the surfactant concentration, air flow rate, pH, and foam height. Under optimal operating conditions obtained through an orthogonal experiment, the maximum enrichment ratio of 48.7 was achieved for riboflavin along with 99.3% removal efficiency. The optimal operating conditions had the concentration of CTAB at 0.3 g/L, air flow rate at 400 ml/min, foam height at 90 cm, and pH at 12. Therefore foam separation proved to be an effective method to recover the riboflavin in terms of the good enrichment and removal efficiency.     

改性Zr-Na/Zeolite双功能沸石脱除水溶液中氨氮和磷性能研究

采用氯化钠离子交换和氯氧化锆沉积沉淀两步法改性天然沸石,得到具有脱除水中氨氮和磷的双功能锆钠改性天然沸石（Zr-Na/Zeolite）,考察了不同pH、溶液初始质量浓度和温度下Zr-Na/Zeolite对氨氮溶液、含磷溶液及氮磷共存溶液的吸附情况。结果表明,Zr-Na/Zeolite能够在保持Na改性沸石（Na/Zeolite）优良的吸附氨氮性能的基础上,极大地提高吸附磷的能力。在不同pH下,Zr-Na/Zeolite 吸附氨氮和磷的效果呈现不同的规律。对于氨氮,水溶液pH在4~8时具有最佳吸附性能,最高吸附量达到4.5 mg/g。对于含磷阴离子,脱磷能力随pH的升高而降低,吸附容量从pH=2时的4.71 mg/g降到pH=10时的2.20 mg/g。溶液初始质量浓度从10 mg/L提高到200 mg/L时,氨氮和磷的单位吸附容量分别从1.42和2.46 mg/g提高到11.6和11.8 mg/g,去除率分别从57.0%和98.2%降低到23.2%和23.6%。溶液温度从25 ℃升高到45 ℃,氨氮的吸附容量提高了10%,磷的吸附容量提高了11%。磷和氨氮的吸附过程符合准二级动力学模型。0.1 mol/L NaOH和1.0 mol/L NaCl混合溶液可以再生Zr-Na/Zeolite,循环吸附14次,吸附效率几乎保持不变。     

Parametric studies on the performance of cation exchange for the ammonium removal

Ion exchange performance to remove ammonium in drinking water was studied experimentally in batch and continuous operation systems under the various conditions. Data were collected using commercially available strongacid cationexchange resins of Na+ and H+ types. The performance was evaluated using equilibrium concentrations for the batch system or the effluent concentration histories for the continuous column system as a function of time or the solution volume passed through the experimental column until resins were exhausted. With high temperature or low initial feed concentration, ammonium removal characteristics of the batch system increase. At the solution concentrations of 0.5, 1.0, and 2.0 mg/L of NH4+-N and the temperatures of 15, 25, and 35 ‡C, the selectivity coefficients of resin were determined between 1.38 and 1.43 for Na+ type resin, and 3.22 and 3.47 for H+ type resin. The selectivity coefficient was correlated as a function of temperature using Kraus-Raridon equation. The breakthrough curves obtained from the continuous column operation give some results; i) with small column diameter or large column height, ii) with low initial feed concentration, iii) with low volumetric flow rate, or iv) with high solution temperature, the ammonium removal for the typical macroporous type resin increase. The results of this study could be scaled up and used as a design tool for the waterpurification systems of the drinking water treatment processes. This paper was presented at The 5th International Symposium on Separation Technology-Korea and Japan held at Seoul between August 19 and 21, 1999.     

烟气脱硫产物亚硫酸铵非催化氧化动力学

采用搅拌反应器,通过改变初始亚硫酸铵浓度、pH值、空气流量、温度以及硫酸铵浓度、不加催化剂,对氨法烟气脱硫产物亚硫酸铵氧化反应动力学进行了研究。实验结果表明:在硫酸铵浓度为0.15 mol/L、温度为35～60℃的溶液中、氧化空气流量为150～400 L/h时,亚硫酸铵的氧化速率随着pH值增加而下降,随着温度和空气流量的增加而增大;当硫酸铵浓度增大时,亚硫酸铵的氧化速率下降;在pH值为5.5时反应的活化能为31.88 kJ/mol。     

电渗析法脱除三羟甲基乙烷中甲酸钠

三羟甲基乙烷中甲酸钠的含量是影响产品性能的重要指标。本文采用电渗析方法代替离子交换树脂法脱除三羟甲基乙烷中的甲酸钠,考察了操作电压、淡室初始浓度、淡室流速、浓室初始浓度等操作条件对脱盐效果的影响。结果表明：操作电压为8V,淡室浓度0.15mol/L,淡室流速0.529cm/s,浓室初始浓度0.01mol/L甲酸钠溶液的条件,脱盐率达到95%,电渗析可有效用于三羟甲基乙烷中甲酸钠的脱除。从环境保护和资源消耗方面考虑,电渗析法优于离子交换树脂法用于脱除三羟甲基乙烷中的甲酸钠。     

双极膜电渗析法分离发酵液中乳酸及离子迁移规律

考察了双极膜电渗析法分离酒糟发酵液中乳酸的影响因素,结果表明:当进料浓度13.5 g·L^-1,工作电压27 V,进料浓度比1.3,流量20 L·h^-1,电渗析10 h,产品罐中的乳酸浓度增加至20.95 g·L^-1,是电渗析前进料罐中的乳酸浓度的1.6倍,具有显著的浓缩效果.酸根离子迁移规律的研究表明,乳酸根离子的迁移速率明显高于其他酸根离子,且丙酸和乙酸的乳酸分离率相对较低.     

Study on Streptomycin Sulfate Recovery by Batch Foam Separation

The feasibility of foam separation as a technique was assessed for the recovery of streptomycin sulfate from the waste solution by using an anionic surfactant sodium dodecyl sulfate (SDS). The experimental parameters examined were SDS concentration, superficial gas velocity, initial pH, and liquid loading volume. The results showed that sodium dodecyl sulfate as the surfactant for foam separation had good foaming quality and could effectively concentrate streptomycin sulfate of the aqueous solution by technology of foam separation. The enrichment ratio and the recovery rate of streptomycin sulfate were 4.0 and 85%, respectively under the best operating conditions of sodium dodecyl sulfate concentration 0.4 g/L, superficial gas velocity 300 mL/min, liquid loading volume 300 mL and initial pH 6.0 when streptomycin sulfate concentration was 0.5 g/L.     

电渗析处理印刷线路板废水的研究

用电渗析技术研究了从印刷线路板废水中精制回收Cu2+的效能。试验结果表明,电渗析能有效富集线路板废水中的Cu2+。当电压为15 V,进水Cu2+、CODCr的质量浓度分别为257、507 mg/L时,Cu2+的富集倍数为2.29,淡室出水的Cu2+质量浓度为0.9 mg/L,Cu2+的去除率达99%,对CODCr的去除率达到43%。但电渗析连续运行结果表明,离子交换膜发生膜污染,产生浓差极化,影响Cu2+的富集,使用的膜还有待改进。     

亚硫酸铵催化氧化实验研究

经济高效的将亚硫酸铵转为硫酸铵,是氨法脱硫工艺的关键。采用氧气作为氧化剂,硫酸钴为催化剂,在搅拌反应器中对亚硫酸铵催化氧化过程进行了实验研究。考察了亚硫酸铵初始浓度、硫酸铵初始浓度、催化剂浓度、反应温度、空气流量、溶液pH对亚硫酸铵氧化率的影响。结果表明：控制亚硫酸铵初始浓度为0.3 mol.L-1,硫酸铵初始浓度为0.3 mol.L-1,硫酸钴为0.001 mol.L-1,空气流量为400 L.h-1,pH为6.0,反应温度50℃,反应4 h后,氧化率达到90%。