Agro-Industrial Waste as Potential Heavy Metal Adsorbents and Subsequent Safe Disposal of Spent Adsorbents

Abstract

Water pollution is an environmental problem that affects the ecosystem and living beings. Adsorption is one of the best technologies for the removal of heavy metals. Since waste recovery is the basis of the Circular Economy, agro-industrial waste is emerging as low-cost adsorbents for these pollutants from wastewater. Residues of pine sawdust, sunflower seed hulls and corn residues mix were evaluated as adsorbents of synthetic aqueous solutions of Ni(II), Zn(II) and Cd(II). These residues were characterized to determine their structure and composition, and to understand the adsorption mechanism. Adsorption efficiencies and capacities for the adsorbents and adsorbates were determined and compared. From the obtained results, it is possible to affirm that all biomasses used are good alternatives to the synthetic materials, with adsorption efficiencies greater than 50%. The order of adsorption was Cd > Zn > Ni. At the concentration range checked, adsorption efficiencies decreased in sawdust when a mixture of all metals together was considered (as present in real sewage). Finally, the heavy metals were immobilized, with efficiencies over 88.5%, in clay ceramics (as brick’s precursors). This procedure would help to minimize the contamination that could be generated by the disposal of spent adsorbents, rarely explored in the literature.

Biosorption of Fluoride from Water Using Aluminum Hydroxide Modified Activated Carbon from Composte Coffee Husk and Corn Cob

“…Water is essential to life as almost every industry depends on it to function. However, because of untreated wastewater entering the environment, the growing population and industrial sector have greatly contributed to the decline in water quality and availability in the twenty-rst century (Simón et al, 2022). Eighty percent of diseases globally are thought to be caused by drinking water of poor quality.…”

Removal of lead ions from wastewater using raw and activated carbon of Pterocarpus santalinoides shell

“…Recently, agricultural waste has been one of the many sources of inexpensive adsorbents that are attracting scientific interest for heavy metal removal due to its availability and abundance, biodegradability in natural and environmental settings, higher ability to adsorb metal ions, high surface area, compatibility, being easily renewable, being eco-friendly, and being more specific in nature (Gupta et al, 2021;Elgarahy et al, 2021). Several agricultural wastes such as rice husk, peanut husk, sawdust, groundnut husk, and potato peel have been studied (Simon et al, 2022;Tsade et al, 2020). Plant-based waste is made up of cellulose, hemicelluloses, and lignin and has various functional groups like carboxyl groups, phenolics, hydroxyls, amides, ethers, methyls, and amines that can act as binding sites on their surfaces to which the metal ions can be effectively adsorbed under normal circumstances through various mechanisms (Bilal et al, 2022;Nleonu et al, 2017).…”

“…(Simon et al, 2022;Nleonu et al, 2017). The FTIR spectra for the raw biomass studied are shown in Figure1.…”

Investigation and optimization of cadmium ion adsorption from wastewater using raw and activated carbon of Pterocarpus santalinoides fruit

“…The agricultural waste materials have shown promising results in the removal of heavy metals from wastewater, either in their natural form or after physical or chemical modifications [10]. Agricultural waste materials are one of the major sources of low-cost adsorbents and they are readily available in large quantities [11]. The selection of carbon-rich adsorbent is very important in wastewater treatment, as heavy metals are removed by complexation or electrostatic interaction between the metal ions and adsorbent surface.…”