Advanced Treatment Process for Brackish Water Desalination

Recent advances in capacitive deionization: A comprehensive review on electrode materials

This paper offers a comprehensive techno-economic analysis of capacitive deionization (CDI) technology, examining its significance in water treatment. The analysis begins with a detailed elucidation of CDI principles,emphasizing its operational framework, and delineating both advantages and limitations. A global overviewsurveys the adoption of CDI across industries worldwide, comparing it with alternative water purification technologies to establish benchmarks in terms of cost, efficiency, and scalability. Central to this analysis is a robust techno-economic assessment framework for CDI, incorporating a multifaceted approach that considers capital investment, operational expenses, and maintenance costs. The paper expounds on methodologies for evaluating cost-effectiveness, providing insights into the economic feasibility of CDI implementation. Furthermore, the study delves into specific case studies within the context of Vietnam, a region facing distinct water quality challenges. Through meticulous examination, the case studies highlight the applicability of CDI in addressing Vietnam’s water issues while conducting a detailed techno-economic analysis of its implementation. Challenges hindering widespread adoption are outlined alongside opportunities for enhancing cost-effectiveness and scalability. Regulatory and policy considerations crucial for promoting CDI technology within Vietnam’s context are also addressed. The paper culminates in a forward-looking assessment, prognosticating the future trajectory of CDI technology in water treatment. Recommendations are provided to optimize CDI’s techno-economic feasibility globally, emphasizing avenues for further research and development. In summary, this paper substantiates the pivotal role of CDI in addressing water treatment challenges, underscoring its potential impact on water sustainability in Vietnam and across the globe within a comprehensive techno-economic framework.

Capacitive deionization technology with multi-stage treatment as an efficient desalination process for agricultural irrigation

Synchronous removal of tetracycline and water hardness ions by capacitive deionization

Research progress on the application of carbon-based composites in capacitive deionization technology

Capacitive deionization (CDI) technology is utilized for efficient treatment of industrial wastewater, characterized by low energy consumption and environmental protection. In order to comprehend the correlation between key experimental parameters and the electrosorption capacity (EC) of heavy metals in CDI technology, this paper employs a genetic algorithm (GA) to optimize a backpropagation artificial neural network (BPANN) for predicting the EC of CDI technology for heavy metal ions, with the characteristics of electrode materials converted into numerical characteristics for further analysis. Compared to the BPANN, the optimized GABPANN model demonstrates superior predictive accuracy. It achieves automatic adjustment of the hidden layer structure, neuron count, and transfer functions. Furthermore, the grey relational analysis indicates that the electrode material and the initial pH value of the solution are pivotal in determining the EC of heavy metal ions. This underscores the efficacy of machine learning (ML) algorithms in forecasting the nonlinear dynamics of CDI systems and elucidates the influence of individual parameters on the efficacy of heavy metal removal.

Advanced strategies for improving the energy efficiency of capacitive deionization technologies

Due to unstainable use of natural water resources, alternative water resources such as brackish water and seawater desalination have been an emerging solution. However, development of desalination capacity is limited due to the high energy requirements for removing salt ions from water. Currently, capacitive deionization technology (CDI), following the working principle of supercapacitors, has attracted considerable attention from academia, industry, and government agency. As compared to conventional desalination technologies, CDI has several advantages including low energy consumption, easy regeneration, high water recovery, and no secondary waste. In CDI, by applying an external electric filed between two parallel of nanoporous carbon electrodes (i.e., carbon aerogel, activated carbons, carbon nanotubes, and graphene), ions can be stored at the electrode/solution interface via electrical double layer (EDL) formation. Additionally, microbial desalination cell (MDC) is a new bioelectrochemical technology for seawater desalination with simultaneous electricity generation and wastewater treatment. Basically, a MDC reactor contains an anode chamber, a desalination chamber, and a cathode chamber. In MDC, microorganisms can oxidize organic waters in wastewater to harvest electric energy, and meanwhile, salt ions can be removed during the electricity generating process. In this study, we propose a hybrid electrochemical desalination system for seawater desalination by coupling CDI device with a MDC reactor. As a result, MDC produced electricity with open circuit voltage of 0.8 V and a current of 3 mA by using bacteria to degrade organic contaminants through anode bacterial oxidation and cathode reduction. In MDC, 91% removal of chemical oxygen demand (COD) in synthetic wastewater can be achieved, and the solution conductivity can be reduced from 17,000 µS/cm to about 200 µS/cm. More importantly, CDI device can be driven by electricity harvesting from the two MDCs in parallel, and as the downstream desalination process to further desalinate salt water. The results of this study can demonstrate the feasibility of the integrated electrochemical MDC-CDI system for simultaneous wastewater treatment, power production, and water desalination. .

Capacitive deionization (CDI) is an electrochemical technology to adsorb ions from solution by alternately charging and discharging two porous electrodes. During charging, a voltage is applied between the electrodes, and ions are adsorbed into electrical double layers (EDLs) formed in the micropores of the electrode. As a result, feed water is desalinated. After the electrodes are saturated with salt, they are discharged and ions are released, resulting in a concentrated effluent stream. Recently there has been an growing scientific and commercial interest in CDI technology, and various applications are considered, such as wastewater remediation for cooling towers, water softening, and desalination of brackish water. In this Thesis we study mechanisms of ion transport and adsorption in CDI technology, and we address three topics: I) energy consumption and resistance identification, II) ion-selective adsorption, and III) long-term operation and pH changes.

Capacitive\ndeionization (CDI), as an energy-efficient and promising\nbrackish water desalination technique, has certain advantages over conventional methods\nsuch as thermal distillation, ultrafiltration, and reverse osmosis.\nHowever, CDI technology is as yet not widely applied as it can only\ntreat low salinity water due to the limitation of salt adsorption\ncapacity of the electrode. The complexity and high cost of the preparation\nof such materials with excellent salt removal capability also hinder\nthe commercialization of CDI technology. To surmount these barriers\nin CDI technology, we hereby developed a hierarchical porous carbon\n(h-PC) which was prepared via a facile, economic, and green calcination\nof biomass mixed with an activator. Our prepared h-PC electrodes demonstrate\nan outstanding salt adsorption capacity (SAC) of 83.0 mg/g when the\nNaCl concentration is 1000 mg/L for batch mode CDI. This SAC is significantly\nhigher than those reported elsewhere (normally between 15–25\nmg/g), and the ultrahigh SAC may be due to the high specific surface\narea (SSA) and favorable hierarchical pore structure of h-PC. The\nas-prepared h-PC can also effectively remove heavy metals and desalinate\nbrackish water with a wide range of salinity up to 10000 mg/L. Furthermore,\nthe h-PC-800 electrode shows outstanding cycling stability with no\ndecline of salt adsorption capacity or its corresponding charge efficiency\nin the long term continuous mode CDI process (over 200 cycles). Our\nstudy of this work may be helpful in the design of practical and economical\nmaterial for high-performance CDI application of the desalination\nof brackish water with various salinity.

Removal of low concentrations of nickel ions in electroplating wastewater using capacitive deionization technology

The existing conventional technologies like Reverse Osmosis, EDI(Electro Deionization), membrane filtration and Ultra Violet filtration offer solutions for drinking water, but various factors like capital and operational cost, ease of operation, maintenance and fouling had been the considerable driving factors to judge the techno-economic paradigm while making a technology selection. Also, the increasing demand for augmenting the safe drinking water calls for novel and sustainable breakthrough technologies. The novel and sustainable technology like Capacitive deionization (CDI) could be a potential alternative which works on electrophoretic phenomenon to provide low TDS (Total Dissolved Solids) drinking water. When water passes between a pair of carbon aerogel electrodes, ionic species are held at the charged electrode surfaces and are removed from the solution during the charging the cycle. After the electrodes become saturated with salts or impurities, the electrodes are regenerated by electrical discharge or polarity reversal, allowing the captured ions to be released into a relatively small purge stream. Thus, CDI can be used to deionize or purify water. An effort is also made to study, evaluate and compare conventional RO technology with Existing CDI technology. Batch ion absorption studies on the newly developed electrodes recorded efficiency with ion removal of 140 ppt using 5 pairs of electrodes (32m 2 area) and the SEM images of the developed electrodes indicated good porosity which in turn illustrates the potential absorption capacity of the developed electrodes. The main factors to be considered while developing an ideal electrode are some of the properties like BET(, electrical conductivity, capacitance, mechanical strength. Correlation studies on the comparison with RO and evaluation of the developed electrodes of the CDI were carried out. I. Introduction The desalination of seawater and brackish groundwater to provide fresh drinking water is an established and thriving industry. Desalinisation refers to any of several processes that removes amount of salt and any other minerals present in the saline water. Salt water is desalinated in order to produce fresh water that is suitable for human consumption or irrigation. The most commonly used technologies at present for the desalination process are Thermal Distillation and Reverse Osmosis (RO) filtration. This report will mainly deal with the research conducted for the development of an ideal electrode which is non-polluting, energy efficient, cost effective and electrically conductive, suitable for an industrial sized capacitive deionisation module. Capacitive Deionisation in other terms can be defined as a powerful desalination module which utilises low-pressure non membrane desalination process. Most of the existing industrial scale desalination centres get their energy from the combustion of fossil fuels, thus in effect exchange potable water for CO2 which causes global warming and eventually contributes to the demise of fresh water. As a result, global warming will lead to increase the need for additional desalination. Therefore, it is imperious to find methods to find desalination of water that are more energy efficient. Thus, electrochemical desalination tools like capacitive deionisation have the potential to be such an energy efficient technology. The main objective of this research is to Evaluate a newly developed electrode for electro adsorption studies and its relevance for CDI technology. Capacitive Deionization technology is evaluated by taking in to consideration factors like construction, operation and maintenance costs to that of reverse osmosis and an head on head evaluation is performed. Taking into consideration brackish type feed water the cost of construction can vary accordingly depending upon various factors. Some of the major factors that influence the design development are:-  Capacity of the water to be treated.  Blending of source water with permeate.  Quality of the feed. (TDS and constituents required removal required)  Concentrate disposal.  Pre and post treatment requirements.

Demand for lithium batteries and lithium resources is growing because of the fast development of electric vehicles which will reach 900,000 metric tons per year by 2025. But the available lithium supplies are running out, and the future utilization of lithium resources will depend on strong productivity and resource recovery. However, current methods of extracting lithium ion resources still have the disadvantages of slow rates, unstable system outputs, and low purity. These methods can hardly compensate for the huge market demand in the future. The alternative technology, capacitive deionization (CDI) technology based on electrochemical ion pumping, provides a high capacity and rate of lithium resource recovery, which uses renewable electrode materials, reduces system waste generation, and has high lithium ion purity in the extract, which is sufficient to meet the future market demand. This mini-review analyzes the electrode materials used in CDI technology with a particular emphasis on the development of three materials, Olivine LiFePO4/FePO4, Spinel LiMn2O4/λ-MnO2, and Spinel LiNi0.5Mn1.5O4. The advantages and disadvantages of the current advanced materials are evaluated from various perspectives, and the feasibility of different electrodes is analyzed.

Review on 2D MXene and graphene electrodes in capacitive deionization

Recent progress in graphene-based and ion-intercalation electrode materials for capacitive deionization