Valorization of Agricultural and Marine Waste for Fabrication of Bio-Adsorbent Sheets

Industrial wastewater often contains considerable amounts of toxic pollutants that would endanger public health and the environment. In developing countries, these toxins are often discharged into natural ecosystems without pretreatment as it requires costly treatment processes, which causes long-term harmful socioeconomic impacts. Employing wastewater treatment plants using physical, biological, and chemical methods to clean the wastewater is considered by many nations the answer to the environmental crises. The treated water could be used for targeting the irrigation systems in its majority, as it is biologically acceptable for that specific use, which economizes the use of freshwater sources for municipal use specifically. This study presents a novel method for fabricating an efficient adsorbent sheet for wastewater treatment. The sheets are fabricated by combining sugarcane bagasse pulp as a scaffold with commercial, naturally activated carbon and bimetallic-prepared adsorbents. Fava beans and algae biomass are utilized in the production of activated carbon because of their high carbon contents, availability, and low cost. The prepared composite sheets are synthesized and investigated for several pollutants’ removal such as methyl orange, crystal violet dyes, and chromium heavy metals. These pollutants are selected due to the high discharge amount and toxic effect on aquatic life. FT-IR and SEM analyses are used to characterize the samples. To determine the mechanism of adsorption, the intra-particle diffuse, pseudo-first-order, and pseudo-second-order kinetic models are used to test the experimental data. All the prepared sheets can retain the pollutants, with the best removal efficiency of 96.24% for methyl orange adsorption onto the bio-composite mixed sheet. For methyl orange, the error values and correlation coefficient R² of 0.971 and 0.951 shows that the Temkin isotherm and pseudo-first-order kinetic model, respectively, are capable of providing the highest goodness of fit for the experimental data. The results of the isotherms and kinetics parameter sets provided valuable proof that the adsorption of methyl orange onto the bio-composite sheet is an endothermic phenomenon involving both chemical and physical adsorption.