把城市废水转变成饮用水

随着人民生活水平的提高以及人口的增长,我国及世界上许多国家和地区,出现了淡水水源不足的问题。为了取得淡水,不惜工本,劈山引水,淡化海水,甚至设法利用     

节水·节约资源·节约能源

水,是一种宝贵的资源,是地球上生命的起源,人类的一切活动均离不开它。但它在地球上的储量,又是有一定限度的,并非取之不尽。据有关资料介绍,地球上虽然有70％的表面积被水覆盖,然而其中淡水只占2.70％,可供开采利用的淡水就更少了,只有0.2％。我国的淡水资源虽然居世界第6位,但人均淡水却居世界第88位,是世界人均淡水的1/4。目前我国许多地方缺水严重,     

反渗透淡化技术的发展近况

一、绪言众所周知,淡水是人类赖以生存的重要物质条件之一。在工业高度发达的今天,淡水的供应尤为重要。目前,世界各国的淡水来源主要依靠江河水流,然而,随着城市不断增加和工农业的飞速发展,     

国内部分水质稳定剂生产情况调查

随着工业的迅速发展和人民生活的需要,淡水用量急剧增加,淡水资源趋于供不应求,已成为人类社会面临的严重问题。目前,全世界有一百多个国家缺乏淡水资源。据有关资料统计,我国人均水资源占有量为2630m~3,相当于世界人均水资源占有量的四分之一,在缺乏淡水资源国家中,列第八十     

水处理全有机配方的研究与应用

1、前言我国是个贫水国家,淡水资源虽居世界第5位,但人均占有淡水量仅相当于世界人均占有量的1/4。随着工业建设的发展,水源不足的潜在危机越来越明显。就遍布全国的1300多个小氮肥厂而言,用循环水代替直流水,合理地使用有限的淡水资源,最大限度地节约用水,减少排污,保护水体,是很有意义的。我们考虑到小氮肥厂水处理工作开展较     

2012全国工业节水及废水资源化技术研讨会(预通知)

时间:2012年6月6—7日地点:上海世博馆会议厅主办单位:工业水处理杂志社支持单位:国家工业水处理工程技术研究中心国家工业节水技术创新服务平台石化工业水处理国家工程实验室我国是世界上严重缺水的国家,人均淡水资源仅相当于世界人均淡水资源的1/4。同时,随着我国     

化肥企业必须严格贯彻“节水·治污·利用”方针

20世纪世界淡水消费量增加6倍，其中工业用水增加约26倍，预测淡水短缺是21世纪面临三大生态问题之一。我国水资源居世界第6住，但人年均水量为世界水平的1／4，列世界第121位，预测2010年内进入严重缺水期，缺水高峰期在2030年左右。我国不但缺水，而且用水浪费、污染水源和利用率低。化肥是用水和排污大户，只要严格贯彻国家有关环境、治污等法规和标准，可以做好节水、治污和利用。     

海水脱盐技术综述

世界人口的增长使淡水的供应紧张。为了缓解淡水供应的压力，海水脱盐受到普遍重视。本义讨论海水脱盐的基本原理，包括已商业应用的热脱盐和膜脱盐技术、脱盐和发电的关系以及脱盐的经济性问题。     

化肥企业必须严格贯彻"节水·治污·利用"方针

20世纪世界淡水消费量增加6倍,其中工业用水增加约26倍,预测淡水短缺是21世纪面临三大生态问题之一.我国水资源居世界第6位,但人年均水量为世界水平的1/4,列世界第121位,预测2010年内进入严重缺水期,缺水高峰期在2030年左右.我国不但缺水,而且用水浪费、污染水源和利用率低.化肥是用水和排污大户,只要严格贯彻国家有关环境、治污等法规和标准,可以做好节水、治污和利用.     

全球首个国际水资源管理标准公布

正据ENS环境新闻服务网报道,世界水资源管理联盟日前发布了全球首个以促进淡水的可持续使用为框架体系的国际水资源管理标准,为淡水资源的使用和可持续管理制定了具有普适性和一致性的规范要求。水资源管理联盟委员会主席、澳大利亚水资源管理联盟代表迈克尔·斯宾塞(Michael Spencer)表示:"保护淡水资源需要跨部门的合作。为了人类和自然界的未来,政府和公民     

Comment on “Carbon nanotube/graphene composite for enhanced capacitive deionization performance” by Y. Wimalasiri and L. Zou

In a recent study, Wimalasiri and Zou [1] have reported the use and performance of composite electrodes of carbon nanotubes (CNT) and graphene for application as porous electrodes in capacitive deionization (CDI). While CDI is emerging as an attractive technology for water desalination, and novel electrode materials and composites are important contributions to the advancement of the field, there are several issues in this study that we must comment on.     

Enhanced capacitive deionization of graphene/mesoporous carbon composites

Capacitive deionization (CDI) with low-energy consumption and no secondary waste is emerging as a novel desalination technology. Graphene/mesoporous carbon (GE/MC) composites have been prepared via a direct triblock-copolymer-templating method and used as CDI electrodes for the first time. The influences of GE content on the textural properties and electrochemical performance were studied. The transmission electron microscopy and nitrogen adsorption-desorption analysis indicate that mesoporous structures are well retained and the composites display improved specific surface area and pore size distribution, as well as pore volume. Well dispersed GE nanosheets are deduced to be beneficial for enhanced electrical conductivity. The electrochemical performance of electrodes in an NaCl aqueous solution was characterized by cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy measurements. The composite electrodes perform better on the capacitance values, conductive behaviour, rate performance and cyclic stability. The desalination capacity of the electrodes was evaluated by a batch mode electrosorptive experiment and the amount of adsorbed ions can reach 731 μg g(-1) for the GE/MC composite electrode with a GE content of 5 wt%, which is much higher than that of MC alone (590 μg g(-1)). The enhanced CDI performance of the composite electrodes can be attributed to the better conductive behaviour and higher specific surface area.     

Membrane-assisted capacitive deionization: Effect of Poly(vinyl alcohol) cross-linking on the properties of ion exchange membranes

Novel composite electrodes were developed for application in membrane capacitive deionization (MCDI). Activated carbon (AC) was dispersed in a solution of poly(vinyl alcohol) (PVA) mixed with polyacrylic acid (PAA) or poly dimethyl diallyl ammonium chloride (PDMDAAC), and cast onto the surface of an AC-based modified graphite electrode, prepared by phase inversion, to form a composite membrane further cross-linked with glutaraldehyde (GA). The effect of the cross-linking on the chemical structure of the PVA-based membranes was determined by attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy. Cyclic voltammetry was conducted to examine the specific capacitance of the composite electrodes. Desalination experiments were then performed with MCDI unit cells to study the effect of cross-linking on the desalination efficiency. It was proved that after optimization, the synthesized composite electrodes exhibited one and a half times higher NaCl removal capacity and three times higher adsorption rate as compared to that of a conventional CDI cell using commercial ion exchange membranes (IEMs) with almost the same energy consumption. The enhanced desalination performance was attributed to the optimized properties of the selected polymers and the improved adhesion of IEMs to the electrodes. This research paves the way for the application of new materials in MCDI processes for improved water desalination.     

Capacitive deionization of NaCl solution with carbon aerogel-silicagel composite electrodes

Carbon aerogel-silica gel composite materials with different kinds of ratios were used as the electrode-activematerials for a capacitive deionization (CDI) process, which were prepared by a paste rolling method. The electrochemical parameters such as current values, coulombs, specific coulombs and coulombic efficiencies were investigated using a unit cell. The composite electrodes showed good wettability and high mechanical strengths with adequate durability under 1,000 ppm NaCl solution. Also, the composite electrodes showed an effective cycle ability without destroying active materials from the composite electrode, which decreased the manufacturing time by 50%. Additions of silica gel obviously improved coulombic results and led to effective performance of the CDI process.     

Atomic layer deposition of TiO2 on carbon-nanotubes membrane for capacitive deionization removal of chromium from water

Chromium (Cr) is a common heavy metal that has severe impacts on the ecosystem and human health. Capacitive deionization (CDI) is an environment-friendly and energy-efficient electrochemical purification technology to remove Cr from polluted water. The performance of CDI systems relies primarily on the properties of electrodes. Carbon-nanotubes (CNTs) membranes are promising candidates in creating advanced CDI electrodes and processes. However, the low electrosorption capacity and high hydrophobicity of CNTs greatly impede their applications in water systems. In this study, we employ atomic layer deposition (ALD) to deposit TiO₂ nanoparticulates on CNTs membranes for preparing electrodes with hydrophilicity. The TiO₂-deposited CNTs membranes display preferable electrosorption performance and reusability in CDI processes after only 20 ALD cycles deposition. The total Cr and Cr(VI) removal efficiencies are significantly improved to 92.1% and 93.3%, respectively. This work demonstrates that ALD is a highly controllable and simple method to produce advanced CDI electrodes, and broadens the application of metal oxide/carbon composites in the electrochemical processes.     

活性炭纤维电极的电容去离子脱盐试验研究

以活性炭纤维为电极材料研制液流式电容去离子模块,考察了电压、进水流量、进水浓度对其脱盐性能的影响。结果表明,活性炭纤维电极用于电容去离子脱盐具有吸附效率高、再生性能好的优点。对活性炭纤维进行载钛改性．改性后的电极单位吸附量提高了31．61％。对于电导率为7．31mS／cm的电镀反渗透浓水,在21级电容去离子模块串联作用下．离子去除率高达95．21％。处理后的电导率与自来水相近,说明以活性炭纤维为电极的电容去离子技术具有广阔的应用前景。     

Stability of a carbon gel electrode when used for the electro-assisted removal of ions from brackish water

A porous carbon gel obtained from the poly-condensation of resorcinol and formaldehyde was synthesized and used as an electrode material for the capacitive deionization (CDI) of synthetic brackish water. The desalting capacity of this material was evaluated in terms of applied voltage and zero-voltage regeneration over a number of cycles, and compared to that of commercially available carbon materials (powdered activated carbon and activated carbon cloth). Due to an adequate combination of chemical and porous features, the deionization capacity of the carbon gel electrode exceeded that of the electrodes based on conventional microporous carbons over a larger number of adsorption/regeneration cycles. An almost fully reversible ionic removal (ca. 90% recovery) was obtained for this electrode material when regeneration was carried out at zero-voltage conditions. Characterization of the cycled electrodes showed that the carbon gel was resistant to electrochemical anodic oxidation under the polarization conditions used (applied voltage of up to 1.2 V), whereas the electrodes produced from the two commercial carbon materials undergo severe modifications (oxidation and a decrease in surface area) when the applied voltage was maintained for several cycles.     

Limitations of charge efficiency in capacitive deionization processes III: The behavior of surface oxidized activated carbon electrodes

In previous papers we reported on attempts to improve the performance of water desalination using capacitive de-ionization (CDI) processes by understanding the ions transport and adsorption/desorption behavior of activated carbon electrodes as a function of the applied potential. We also investigated the charge efficiency in CDI processes of brackish water in symmetrical cells containing identical highly porous activated carbon electrodes. In this work, we study the influence of oxygen-containing surface groups on activated carbon electrodes on the adsorption/desorption behavior of ions in brackish water. A special methodology was developed in order to estimate the charge efficiency of CDI processes which include the ability to prepare various kinds of activated carbon electrodes (ACEs) with controlled porosity and surface groups, measuring the PZC (potential of zero charge) of ACE in solutions and simultaneous adsorption and desorption of ions into/from them. The presence of polar, oxygen containing surface groups on ACE does not affect the electroadsorption behavior of Na⁺ and Cl⁻ ions into porous carbons whose average pore size is greater than 0.58 nm, apart of considerably changing the PZC. This results in a shift of the entire curves of ion adsorption vs. potential. The possible use of ACE with oxidized surfaces in CDI processes is discussed.     

ZIF衍生多孔碳纳米纤维用于高效电容去离子的研究

作为一种环保节能的新兴脱盐技术，电容去离子技术正在成为替代反渗透脱盐和电渗析脱盐的一项重要的脱盐技术。各种碳基材料被广泛地应用于电容去离子电极材料的研究，然而大多数碳基材料为粉末状材料，需要添加黏结剂，这必将导致电极材料电吸附能力的下降。利用静电纺丝技术，将ZIF纳米颗粒和聚丙烯腈混纺，并通过分段高温热处理过程，成功合成了具有柔性结构的整体性多孔碳纳米纤维。由于其具有孔道结构的分级分布和较强的亲水性等优良特性，所制得的多孔碳纳米纤维在1.2 V电压下于500 mg/L NaCl溶液中表现出良好的电吸附性能，脱盐量达到了19.92 mg/g，比普通碳纳米纤维提高了一倍以上。     

Endeavor toward competitive electrochlorination by comparing the performance of easily affordable carbon electrodes with platinum

Kinetics of chloride ion oxidation was studied on graphite, glassy carbon (GC), and platinum electrodes. The performance of the electrodes was monitored using the cumulative productivity and current efficiency of the cell as indicators. It was seen that the performance of the working electrode improved with repeated uses, the current efficiency increased from 22% in the third use to about 46% in the tenth use. The study also revealed that the role of diffusion to the total anodic current was insignificant and chloride ions were transported at the electrode surface only by conduction. The hypochlorite production in case of platinum was about 3.66 times than that of graphite and GC with the current efficiency of 75% in contrast to 46% found in graphite and GC. But platinum undergoes passivation to a significant extent unlike the graphite and GC electrodes. Chronopotentiometry experiments confirmed the passivation process in platinum electrodes, showed a steep rise in potential from 1.2 to 2?V while the electrode potential was uniformly maintained at 1.7?V in carbon electrodes. The highest i_o, exchange current density value was observed at 0.45?mA/cm² in 0.5?M electrolyte, which is an indication of improved electrocatalytic activity with increased molar concentration. After continuous uses the corrosion rate studies revealed that platinum and GC electrodes were corrosion resistant whereas graphite underwent corrosion at the rate of 0.006?mm/h. The study dictated that carbon electrodes has great potential to be used as an alternatives to platinum electrodes, however, further investigations are required to assess its practical applicability in the public water supply system.