Saleh A. Ahmed

By Ziad Moussa, Zaher M.A. Judeh and Saleh A. Ahmed

Nonenzymatic exogenous and endogenous antioxidants play an important role in human health and act as preservatives for cosmetics, pharmaceuticals, and food products. This chapter will discuss the chemical structure and mechanism of action of the most important nonenzymatic small exogenous and endogenous organic molecules that act as antioxidants. The chapter will focus on the structural features, functional groups, properties, biosynthetic origin, and mechanism of action of such antioxidants. It also covers damages that free radicals create and the mechanisms by which they are neutralized by the various antioxidants. The scope of this chapter will be limited to nonenzymatic exogenous and endogenous antioxidants since enzymatic antioxidants have been discussed extensively in several reviews.

Part of the book: Free Radical Medicine and Biology

By Mohammad Muneer, Ziyaur Rasool, Shreya Parashar, Abdulaziz M. Almohyawi, Ziad Moussa and Saleh A. Ahmed

The semiconductor photocatalysis has been the subject of much research interest in the recent decades due to its potential future technology for energy conversion and environmental remediation. Graphitic carbon nitride (g-C₃N₄) is a promising semiconductor photocatalyst due to its metal-free structure and responsiveness to visible light. However, its pristine form exhibits limitations such as poor solar absorption and rapid charge carrier recombination, which reduces photocatalytic efficiency. Various modification strategies, like doping and heterojunction formation, have significantly improved its optical and electronic properties, paving the way for advanced applications in environmental remediation and energy conversion. This review has emphasized the synthesis, advantages/disadvantages, and mechanistic aspects of g-C₃N₄ for the degradation of organic pollutants in aqueous suspension. In addition, the review discusses the use of different strategies such as doping of metals or non-metals, co-doping, and generation of heterojunction for modified g-C₃N₄ photocatalyst. These strategies alter the electronic and structural properties by greatly increasing the optical absorption behavior, enhancing charge separation, and prolonging the lifetime of charge carriers.

Part of the book: Transition Metals