A critical review on non-metal doped g-C3N4 based photocatalyst for organic pollutant remediation with sustainability assessment by life cycle analysis.

Photocatalysis is recognized to be one of the most promising ways to address energy and environmental issues by utilizing visible light. Graphitic carbon nitride (g-C3N4), with a moderate band gap (∼2.7 eV) has been the flashpoint in environmental photocatalysis as it can work better under visible light, can be synthesized by a facile synthesis process using low-cost materials, thermally and chemically stable. Still the photocatalytic performance of g-C3N4 is not satisfactory because of certain limitations such as insufficient visible light absorption capacity, low electron-hole separation efficiency, high recombination rate, poor surface area. Introduction of doping, band structure engineering, defecting and designing of heterojunction, composites etc. were investigated to amplify its applications. Among all these modifications, elemental doping is a suitable and successful alternative for the enhancement of the photocatalytic activity by changing the optical and electronic properties. This review emphasizes on advancement and trends of elemental doping and its application on photocatalytic organic pollutant remediation in aqueous medium. The fundamental photocatalytic activity of heterogeneous photocatalysis and specifically g-C3N4-based photocatalysis have been discussed. The benfits of non-metal doping, enhanced photocatalytic performance by doping element, mechanism invloved in doping, advantages of co-doping has been explained. Mono, bi, and tri non-metal doped g-C3N4 and their application for the removal of organic pollutants from water medium by visible light photocatalysis has been summerized. Life cycle assessment (LCA) of photocatalytic system has been highlighted. Future research should focus on the large-scale application of the photocatalysis process considering the economic aspects. A rigorous life cycle assessment for deploying the non-metal doped g-C3N4-based photocatalysis technology for successful commercial application is recommended.

A mini-review on arsenic remediation techniques from water and future trends.

Arsenic contamination is a severe issue because of its toxicity and related health risks. This review article presents an overview of the sources, health hazards, and treatment options for arsenic pollution. Conventional approaches to achieving the permitted level of 10 ppb set by the WHO, such as chemical oxidation, biological oxidation, and coagulation-flocculation, are ineffective and time-consuming. The paper analyses the advantages and disadvantages of various advanced treatment technologies, including membrane filtration, ion exchange, advanced oxidation, phytoremediation, and adsorption. This paper summarized the effectiveness of hybrid arsenic remediation techniques in removing arsenic and its operating conditions. This study is a helpful tool for putting remediation strategies into practice. This article describes arsenic pollution's damaging effects on human health, underscoring the necessity for careful treatment. The article addresses numerous treatment technologies, each with advantages and disadvantages preventing widespread use. Due to these limitations, deciding the best technique for arsenic remediation is difficult. As a result, hybrid treatment systems are urgently needed, with photocatalysis-adsorption being the most popular approach. The relevance of adaptable, user-friendly, low-maintenance hybrid technologies that are versatile, easy to use, and provide affordable arsenic removal options, especially for poor populations, is highlighted by prospects.