The Lophira alata wood sawdust obtained for this study was first thoroughly washed with distilled water to remove impurities, then dried under controlled conditions, and subsequently divided into two equal portions. The first portion was retained and used directly as the unmodified sawdust sample. The second portion underwent further treatment: it was carbonized at a temperature of 600 °C for 4 hours to enhance its structural properties, and then chemically activated using 2 M KOH for 24 hours at room temperature to improve its adsorption capacity. Both prepared samples were utilized as adsorbents for the removal of Nickel (Ni²⁺) ions from aqueous solutions. Key operational parameters affecting adsorption, including contact time, adsorbent dosage, and pH, were systematically investigated. Additionally, the physicochemical characteristics of both adsorbents were evaluated to understand their performance. The results revealed that increasing the sawdust dosage, contact time, and solution pH significantly enhanced the adsorption efficiency. Moreover, the activated-carbonized sawdust demonstrated a higher adsorption capacity compared to the unmodified sample. Therefore, Lophira alata sawdust, particularly in its activated-carbonized form, is an effective, low-cost material for removing toxic heavy metals from wastewater.
Chikwe et al. (Thu,) studied this question.