Abstract
Nickel is a major threat to the wastewater discharged from industries, where it is used, because it is classified as a carcinogenic heavy metal. Due to the need to treat polluted water with the highest efficiency and lowest cost, the promising adsorption technology using agricultural waste has proven to be an effective solution for treating water pollution with various pollutants. This study is concerned with determining the ability of a household waste to remove nickel from contaminated aqueous solutions by the adsorption method at different operating conditions. Waste tea leaves (WTL), which are discarded in huge quantities annually, showed noticeable nickel removal efficiency at more than 74% at acidity, shaking, concentration, time, temperature, and adsorption dose of 6, 350 rpm, 42 ppm, 120 min, 20°C, and 5.5 g, respectively. Although the adsorbent used had a low surface area of 12.251 m2/g, FTIR test before and after adsorption confirmed the presence of various functional groups capable of efficiently performing the adsorption function. Furthermore, FESEM test showed that the adsorption medium suffered significant changes compared to what it was before treatment with contaminated solutions. The use of toxic adsorption residues in a beneficial way was tested by adding them to concrete mixtures and studying the compressibility performance. The results showed that the additives increased the compressive strength of the concrete by more than double before it reached the failure point. Thus, this investigation confirmed the possibility of achieving the concept of zero residue level through waste management in an eco-friendly manner. Keywords: Adsorption, Concrete additives, Nickel, Waste tea leaves, Zero residue level.
