Effective Utilization of Agricultural Waste for Removal of Heavy Metals from Waste Streams

Abstract

The progress of industrialization and urbanization poses a great threat to the comfort of people's lives. The production and disposal of large amounts of toxic pollutants have severely polluted our environment. The most hazardous contaminants in soils and surface waters include some organic compounds, like synthetic dyes (SD) and toxic substances (heavy metals). It is of great interest worldwide due to its toxicity to many organisms. An important topic is the use of environmentally friendly agricultural byproducts/ wastes as raw materials or in the production of so-called activated carbon (AC). Our literature review shows that the main factors that characterize these materials are affordability, local availability, and efficiency in removing many unwanted toxins and contaminants. Therefore, it can be used in place of traditional, more expensive adsorbents, especially in developing countries. Many areas lack adequate individual sewage treatment plants. Even if they exist, they lack sufficient functionality and
maintenance due to a lack of sufficient budget. This overview provides several case studies. According to our analysis, these adsorbents are widely utilised in the treatment of wastewater because they exhibit a number of exceptional physical and chemical features. These compounds' adsorption effectiveness depends on the precursor's physical and chemical characteristics (i.e., agricultural waste or byproducts), the characteristics of the activated carbon, and the activation method employed (chemical or physical). Numerous variables, including activation time, temperature, and the addition of an oxidising agent to the initial precursor, might influence the resulting ACs' structural characteristics. Both types are adsorbents that are widely used in wastewater treatment. Our analysis reveals that these adsorbents have a number of exceptional physical and chemical characteristics that make them popular adsorbent materials in treating wastewater. The effectiveness of these chemicals' adsorption depends on the physicochemical characteristics of the precursor (agricultural waste or byproducts), the characteristics of AC, and the type of activation method used, which can be either chemically or physically. Numerous variables, including as activation time, temperature, and the addition of additional oxidants to the initial precursor, might influence the final AC's structural characteristics.