Heavy metals like arsenic, copper, cadmium, chromium, nickel, zinc, lead, and mercury are major pollutants of fresh water reservoirs because of their toxic, non-biodegradable, and persistent nature. The industrial growth is the major source of heavy metals introducing such pollutants into different segments of the environment including air, water, soil, and biosphere. Heavy metals are easily absorbed by fishes and vegetables due to their high solubility in the aquatic environments. Hence, they may accumulate in the human body by means of the food chain. Various methods have been developed and used for water and wastewater treatment to decrease heavy metal concentrations. These technologies include membrane filtration, ion-exchange, adsorption, chemical precipitation, nanotechnology treatments, electrochemical and advanced oxidation processes. In this review, the methods as well as their mechanisms and efficiency are discussed.

Removal of Heavy Metals from Industrial Wastewaters: A Review

Ultrafiltration (UF) is one of the best options for both one-stage and as part of multi-stage water and wastewater purification. This review summarises the known facts about the fouling processes and cleaning procedures and details of the most successful physical and chemical cleaning combinations. The optimum cleaning is closely linked to the nature of the fouling. Precise knowledge of both the fouling type (organic, inorganic, or biological) and the fouling mechanism (gel formation, adsorption, deposition, pore blockage, or cake formation) is the key to success in UF membrane cleaning.

Fouling and cleaning of ultrafiltration membranes: A review

Fouling on ion-exchange membranes: Classification, characterization and strategies of prevention and control.

This review provides insight into the implementation of membrane technology in the petroleum industry for treating produced water that is generated from conventional oilfields in upstream and downstream processes. The ever-evolving and increasingly stringent regulatory standards for discharging produced water pose colossal environmental and economic implications because the bulk of this produced water is disposed into the environment. Thus, a review of the implementation of membrane technology for produced water treatment could contribute to the knowledge required for the increased introduction of scaled-up membrane technology in the petroleum industry. This review encompasses the capabilities and performance optimization possibilities of microfiltration, ultrafiltration, nanofiltration, and reverse osmosis membranes. The level of applications that these membrane technologies might attain within the petroleum industry were determined, and these implementations were correlated with the purpose, performance efficiency, treatment system configurations, necessary pretreatment procedures, quality of treated produced water, fouling occurrence and control, foulants, cleaning procedures, raw produced water content, potential challenges with corresponding applied solutions, and economic factors. This review also maps current and future trends and provides a perspective on the outlook for advances in novel membrane applications for produced water treatment.

Challenges and trends in membrane technology implementation for produced water treatment: A review

Materials chemistry and the futurist eco-friendly applications of nanocellulose: Status and prospect

Fouling is, and will remain, a significant problem in membrane filtration. Most previous fouling studies have determined the effects caused by a single type of foulant. However, in many water purification applications, the feed solutions are often complex, containing multiple foulant types. Existing analyses based on the contribution of individual foulant types do not suffice to explain the complex interactions which occur during mixed-feed fouling behaviour. This article presents a review of fouling studies for feeds containing a mixture of foulant types, with an emphasis on microfiltration and ultrafiltration systems for water purification. Two types of mixed-feed fouling systems are considered: mixtures of different types of macromolecules (such as NOM and polysaccharides); and mixtures of macromolecular and colloidal particles (such as kaolinite). The presence of metallic ions and organic solutes is also considered. Macromolecular adsorption often initiates the fouling, and leads to irreversible flux ...

Xiafu Shi

Papers

Fouling and cleaning of ultrafiltration membranes: A review

Review of fouling by mixed feeds in membrane fi ltration applied to water p urifi cation