A review of graphdiyne: A new material for synthesizing effective adsorbents for aqueous contaminants

Abstract

Graphdiyne (GDY), a new two-dimensional (2D) carbon molecule, is expected to have applications in the removal of contaminants from aqueous media. It has superior conjugation, unusual and varied electronic properties, and exceptional chemical and thermal stability because of its framework of sp and sp2 hybridized carbon bonds that are combined to produce benzene rings and diacetylenic bonds in a two-dimensional symmetrical network. Its molecular chemistry is the result of it having carbon-carbon triple bonds, with a regular distribution of triangular pores in its structure, which provide reaction sites and various reaction pathways. GDY is an adsorbent with an excellent efficiency for the removal of oil, organic pollutants, dyes, and metals from contaminated water, but there is limited evidence of it being used as an adsorbent in the literature. This review discusses its synthesis and its use as an adsorbent together with its prospects for pollutant removal.

1. Introduction

Rapid urbanization and industrialization are increasing global energy demand, which severely contaminates water. The environment and human life are seriously impacted by heavy metals, organics, toxic dyes, and other pollutants released into water by industrial and household processes. The management and elimination of environmental pollution have become one of the most important concerns that have to be tackled. In order to deal with the expanding issue of aqueous pollutants, numerous cutting-edge techniques, including physical, chemical, and biological approaches, have been created recently. These methods rely on certain substances with distinct capabilities to control and remove the pollution.

Aqueous contaminants can currently be removed using a variety of methods, including chemical precipitation, ion exchange, membrane filtering, electrochemical oxidation, photocatalytic degradation, and adsorption. Chemical precipitation is inexpensive, but it struggles with removal of low heavy metal ion concentrations and produces a lot of sludge. While ion exchange technique does not include sludge production, but is more expensive. Electrochemical technologies are more efficient and produce less sludge, but they require significant upfront investments and also expensive power supply. Membrane filtration provides great selectivity and efficiency but incurs increased operational costs due to membrane fouling and decreased permeate flux. Because of its potential to harness infinite solar energy and lack of secondary harmful byproducts, semiconductor-based photocatalysis is gaining popularity in advanced oxidation processes. However, some serious drawbacks of photocatalysts like limited solar activity and rapid electron-hole pair recombination restrict the range of their applications. Adsorption is one of the most competitive and widely utilized treatments among them due to its low cost, ease of use, broad applicability, simplicity of recovery, and lack of by-product formation throughout the treatment process.