A comprehensive review on synthesis and application of nanocomposites for adsorption of chromium: status and future prospective

The presence of heavy metals in water bodies can cause major problems for human, plant, and animal life. Excessive amounts or over the prescribed limits of heavy metals in water bodies usually contaminates the water, this type of water is called polluted water and this whole process is known as water pollution. Regular consumption of heavy metal-contaminated water above prescribed limits can cause various diseases and sometimes even lead to death. Heavy metals like chromium, arsenic, lead, mercury etc. are more toxic and are easily found in water bodies due to anthropogenic and natural activities. The presence of these heavy metals in water even in tiny concentrations is dangerous to human and animal health. Due to its highly toxic nature, it is paramount to remove these pollutants from water bodies before human use. Adsorption is the best technique to remove these pollutants from wastewater based on cost, efficiency, and feasibility. For the adsorption process, a variety of adsorbent materials have been synthesized by researchers in the past few decades, and yet it remains a challenge for researchers and scientists to synthesize a cost-effective and highly efficient adsorbent. In this prospect, water treatment by adsorption process, nano-composites are emerging materials that show excellent adsorption characteristics due to their outstanding material properties, manageable and low-cost production, and excellent adsorption capacity for chromium adsorption from wastewater. The various nanocomposite adsorbent material prepared by different types of nanoparticles that are supported or embedded on biomass/biochar/graphene/polymer/etc. and used for chromium adsorption have been incorporated. The physio-chemical and structural characteristics of nanocomposites are covered in this review paper. Furthermore, the impact of various adsorption conditions, together with their benefits and drawbacks, on the effectiveness of water treatment are discussed. This thorough review concludes with a summary and some ideas about novel strategies and difficulties in the investigation of advanced and hybrid nanocomposite materials used to remove Cr(VI) from wastewater.