The structure of malachite green (MG) molecules makes them highly resistant to environmental degradation, posing significant challenges for removal. Similarly, heavy metals such as Ni2+ present substantial risks due to their toxicity and persistence. The presence of MG and Ni2+ in water and wastewater is frequently reported at levels exceeding standard limits, highlighting the urgent need for effective removal and degradation strategies. Herein, EDTA-functionalized magnetic activated carbon (EDTA-FMAC) derived from sunflower stems was developed and successfully applied for the removal of MG and Ni2+ from contaminated water. The adsorbent (MAC) was characterized using FTIR, XRD, SEM, Raman, VSM, and BET techniques. Key factors, including sorbent weight, contact time, initial pollutant concentration, and pH, were optimized using Response Surface Methodology (RSM). The study achieved maximum adsorption efficiencies of 97.68% for MG and 94.63% for Ni2+ at initial concentrations of 15 and 20 mg/L, adsorbent weights of 9 and 20 g, contact times of 25 and 20 minutes, and pH levels of 6 and 4, respectively. The experimental data aligned closely with the Freundlich isotherm model and the pseudo-second-order kinetic model. Thermodynamic analysis indicated that MG and Ni2+ adsorption onto magnetic activated carbon is endothermic and spontaneous. This study demonstrates that EDTA-functionalized magnetic activated carbon derived from sunflower stems is an efficient, effective, and reusable adsorbent for the removal of MG and Ni2+ from tap water.
Aghazadeh et al. (Sun,) studied this question.