Malachite green removal by activated potassium hydroxide clove leaf agrowaste biosorbent: characterization, kinetic, isotherm, and thermodynamic Studies

Abstract

The obliteration of the quality of water, soil, and air due to the fast-growing global population and industrialization is critical for life sustenance on earth. Water quality has exceptionally declined owing to the untreated effluents discharged into streams, oceans, and lakes, by the processes of mining, textile, paint and dye productions, and metal plating [1]. Among these noxious and aromatic contaminants released into water bodies devoid of the preceding appropriate treatment, the textile industry is a primary user of synthetic or noxious dyes for product colouring [2].

Dye is a major source of serious contamination owing to fast industrial development and extensive utilization [3]. Major consideration has been drawn by pollution of water by dye discharge from paper production, food processing, textile dyeing, paints, and cosmetic industries owing to community health and ecosystem hazards. At present, the worldwide colourant market is about 32 billion United States Dollars (USD) and is projected to grow to 42 billion USD in 2021. Yearly, the total of synthetic dyes manufactured is estimated to be over 700,000 tons, and over 15% of these synthetic colourants are yearly discharged into water. Water polluted by these dyes is noxious, xenobiotic, and carcinogenic, and they are grouped according to their chromophore structure into the solvent, reactive, basic, vat, and direct dyes. Exclusively, 47% of synthetic dyes are decomposable [4].

MG is a cationic dye and is positively (+ve) charged in a water-soluble solution. It has a three-benzene ring structure compound as shown in Figure 1, with a molecular formula of C23H25CIN2 and a molecular weight of 364.917 g/mol [5, 6]. It is a synthetic triarylmethane dye and a natural compound utilized as a dyestuff and has appeared as a contentious agent in aquaculture as an ectoparasiticide and fungicide owing to its effectiveness and minimal cost. It is conventionally employed as a dye for materials like silk, wood, acrylic, paper, and leather. However, their intense colour causes a horrible colour to water bodies, and it is intractable to degrade by light and other oxidizing agents, heightening concerns for the environment and making its confiscation challenging. It is extremely noxious to animal cells, carcinogenic, and mutagenic and causes inflammation to the skin. Various health problems associated with the use of MG include a reduction in red blood cell (RBC) count (dyscrasia) and enhanced white blood cell count (leukocytosis), haemoglobin (anemia), and interruption of blood coagulation, eye blisters, wild breathing, and copious sweating. Also, associated with MG utilization is the impairment to the kidney, liver, spleen, and heart and infliction of lacerations on the skin, eyes, lungs, and bones which produces teratogenic impacts [1, 3, 5, 7]. Therefore, there is an urgent need for the adaptation of eco-friendly approaches for the treatment of MG effluents before their release into water bodies and streams to safeguard the ecosystem [1]