scholarly journals Microfiltration and Ultrafiltration Membranes for Water Purification

2021 ◽  
pp. 33-68
Author(s):  
P. Banerjee

Random and rampant urbanization have rendered one third of the global population vulnerable to water scarcity. For mitigating this problem, membrane technology has been widely investigated for desalination as well as reuse and reclamation of wastewater. Polymeric membranes have reportedly displayed significantly lower consumption of energy with potential self-cleansing and antifouling. Application of microporous and ultraporous polymeric membranes for water purification has been vividly discussed herein. The diverse facets of water treatment technologies using polymeric membranes compiled herein will facilitate all potential readers like academicians, environmentalists, industrialists and membrane technologists, and to address the water scarcity challenges of our society.

2018 ◽  
Vol 53 ◽  
pp. 04032 ◽  
Author(s):  
Feng LIN ◽  
Shoubin ZHANG ◽  
Guoqiang MA ◽  
Liping QIU ◽  
Huajun SUN

In recent years, ceramic membranes have been widely used in the field of water and wastewater treatment by virtue of their advantages over conventional water treatment technologies. In this article, definition, classification and characteristics of ceramic membrane were introduced firstly. And then the application of ceramic membrane technology used in various fields of water and wastewater treatment was highlighted. Finally, several opinions on the development prospects of ceramic membrane technology were raised.


2020 ◽  
Author(s):  
Ruobin Dai ◽  
Hongyi Han ◽  
Tianlin Wang ◽  
Jiayi Li ◽  
Chuyang Y. Tang ◽  
...  

Commercial polymeric membranes are generally recognized to have low sustainability as membranes need to be replaced and abandoned after reaching the end of their life. At present, only techniques for downcycling end-of-life high-pressure membranes are available. For the first time, this study paves the way for upcycling fouled/end-of-life low-pressure membranes to fabricate new high-pressure membranes for water purification, forming a closed eco-loop of membrane recycling with significantly improved sustainability.


Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1338 ◽  
Author(s):  
Klara Perović ◽  
Francis M. dela Rosa ◽  
Marin Kovačić ◽  
Hrvoje Kušić ◽  
Urška Lavrenčič Štangar ◽  
...  

Clean water and the increased use of renewable energy are considered to be two of the main goals in the effort to achieve a sustainable living environment. The fulfillment of these goals may include the use of solar-driven photocatalytic processes that are found to be quite effective in water purification, as well as hydrogen generation. H2 production by water splitting and photocatalytic degradation of organic pollutants in water both rely on the formation of electron/hole (e−/h+) pairs at a semiconducting material upon its excitation by light with sufficient photon energy. Most of the photocatalytic studies involve the use of TiO2 and well-suited model compounds, either as sacrificial agents or pollutants. However, the wider application of this technology requires the harvesting of a broader spectrum of solar irradiation and the suppression of the recombination of photogenerated charge carriers. These limitations can be overcome by the use of different strategies, among which the focus is put on the creation of heterojunctions with another narrow bandgap semiconductor, which can provide high response in the visible light region. In this review paper, we report the most recent advances in the application of TiO2 based heterojunction (semiconductor-semiconductor) composites for photocatalytic water treatment and water splitting. This review article is subdivided into two major parts, namely Photocatalytic water treatment and Photocatalytic water splitting, to give a thorough examination of all achieved progress. The first part provides an overview on photocatalytic degradation mechanism principles, followed by the most recent applications for photocatalytic degradation and mineralization of contaminants of emerging concern (CEC), such as pharmaceuticals and pesticides with a critical insight into removal mechanism, while the second part focuses on fabrication of TiO2-based heterojunctions with carbon-based materials, transition metal oxides, transition metal chalcogenides, and multiple composites that were made of three or more semiconductor materials for photocatalytic water splitting.


Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2091
Author(s):  
Angela Spoială ◽  
Cornelia-Ioana Ilie ◽  
Denisa Ficai ◽  
Anton Ficai ◽  
Ecaterina Andronescu

During the past few years, researchers have focused their attention on developing innovative nanocomposite polymeric membranes with applications in water purification. Natural and synthetic polymers were considered, and it was proven that chitosan-based materials presented important features. This review presents an overview regarding diverse materials used in developing innovative chitosan-based nanocomposite polymeric membranes for water purification. The first part of the review presents a detailed introduction about chitosan, highlighting the fact that is a biocompatible, biodegradable, low-cost, nontoxic biopolymer, having unique structure and interesting properties, and also antibacterial and antioxidant activities, reasons for using it in water treatment applications. To use chitosan-based materials for developing nanocomposite polymeric membranes for wastewater purification applications must enhance their performance by using different materials. In the second part of the review, the performance’s features will be presented as a consequence of adding different nanoparticles, also showing the effect that those nanoparticles could bring on other polymeric membranes. Among these features, pollutant’s retention and enhancing thermo-mechanical properties will be mentioned. The focus of the third section of the review will illustrate chitosan-based nanocomposite as polymeric membranes for water purification. Over the last few years, researchers have demonstrated that adsorbent nanocomposite polymeric membranes are powerful, important, and potential instruments in separation or removal of pollutants, such as heavy metals, dyes, and other toxic compounds presented in water systems. Lastly, we conclude this review with a summary of the most important applications of chitosan-based nanocomposite polymeric membranes and their perspectives in water purification.


Water ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1094
Author(s):  
Emily S. Bailey ◽  
Nikki Beetsch ◽  
Douglas A. Wait ◽  
Hemali H. Oza ◽  
Nirmala Ronnie ◽  
...  

It is estimated that 780 million people do not have access to improved drinking water sources and approximately 2 billion people use fecally contaminated drinking water. Effective point-of-use water treatment systems (POU) can provide water with sufficiently reduced concentrations of pathogenic enteric microorganisms to not pose significant health risks to consumers. Household water treatment (HWT) systems utilize various technologies that physically remove and/or inactivate pathogens. A limited number of governmental and other institutional entities have developed testing protocols to evaluate the performance of POU water treatment systems. Such testing protocols are essential to documenting effective performance because inferior and ineffective POU treatment technologies are thought to be in widespread use. This critical review examines specific practices, procedures and specification of widely available POU system evaluation protocols. Testing protocols should provide standardized and detailed instructions yet be sufficiently flexible to deal with different treatment technologies, test microbe priorities and choices, testing facility capabilities and public health needs. Appropriate infectivity or culture assays should be used to quantify test enteric bacteria, viruses and protozoan parasites, or other appropriate surrogates or substitutes for them, although processes based on physical removal can be tested by methods that detect microbes as particles. Recommendations include further research of stock microbe production and handling methods to consistently yield test microbes in a realistic state of aggregation and, in the case of bacteria, appropriately physiologically stressed. Bacterial quantification methods should address the phenomenon of bacterial injury and repair in order to maximally recover those that are culturable and potentially infectious. It is only with harmonized national and international testing protocols and performance targets that independent and unbiased testing can be done to assure consumers that POU treatment technologies are able to produce water of high microbial quality and low health risk.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Eric N. Guyes ◽  
Amit N. Shocron ◽  
Yinke Chen ◽  
Charles E. Diesendruck ◽  
Matthew E. Suss

AbstractEmerging water purification applications often require tunable and ion-selective technologies. For example, when treating water for direct use in irrigation, often monovalent Na+ must be removed preferentially over divalent minerals, such as Ca2+, to reduce both ionic conductivity and sodium adsorption ratio (SAR). Conventional membrane-based water treatment technologies are either largely non-selective or not dynamically tunable. Capacitive deionization (CDI) is an emerging membraneless technology that employs inexpensive and widely available activated carbon electrodes as the active element. We here show that a CDI cell leveraging sulfonated cathodes can deliver long-lasting, tunable monovalent ion selectivity. For feedwaters containing Na+ and Ca2+, our cell achieves a Na+/Ca2+ separation factor of up to 1.6. To demonstrate the cell longevity, we show that monovalent selectivity is retained over 1000 charge–discharge cycles, the highest cycle life achieved for a membraneless CDI cell with porous carbon electrodes to our knowledge, while requiring an energy consumption of ~0.38 kWh/m3 of treated water. Furthermore, we show substantial and simultaneous reductions of ionic conductivity and SAR, such as from 1.75 to 0.69 mS/cm and 19.8 to 13.3, respectively, demonstrating the potential of such a system towards single-step water treatment of brackish and wastewaters for direct use in irrigation.


2016 ◽  
Vol 20 (2) ◽  
pp. 104-110 ◽  
Author(s):  
Eunyoung Jang ◽  
Seongpil Jeong ◽  
Eunhyea Chung

Author(s):  
Liming Huang ◽  
Tingting Yan ◽  
Alaa El Din Mahmoud ◽  
Shuangxi Li ◽  
Jianping Zhang ◽  
...  

The crisis of water scarcity has become one of the most urgent issues to be settled. It is still a challenge to develop a highly efficient water purification technology. In...


Author(s):  

Sorption characteristics of “Ekozol-401” high-dispersed solid-phase agent in water solutions containing ions of iron, aluminum and manganese have been studied. Influence of the sorbent content, extracted metals’ concentration, saline background, hardness and alkalinity, water hydrogen indicator value as well as amount of modifier contained in the solid-phase agent have been stated. High degree of water purification in terms of the said ions has been demonstrated.


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