Effective removal of Ni(II) ions from its aqueous solution by utilizing Euphorbia thymifolia as an adsorbent

Since the electroplating and alloy industries continuously pollute water resources, this paper presents a novel adsorbent to adsorb nickel ions from aqueous solutions prepared in the lab. Chhotidudhi, a creeping weed that is commonly called Euphorbia thymifolia, was used as an adsorbent in its pristine and activated forms. In order to characterize the structure, morphology, and thermal properties of ground Euphorbia thymifolia (ETR) and activated Euphorbia thymifolia (ETA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), and thermal gravimetric analysis (TGA) were used. It was observed that the FTIR spectrum showed different functional groups, such as OH, CH, CO, CN, and CF, which indicated a strong bond with metals. XRD and SEM revealed that the adsorbent is amorphous with a porous structure. Additionally, different adsorbent doses, contact times, pH, concentrations, and temperatures were investigated. Approximately 2 h was required for effective adsorption with an initial concentration of 20 mg/L, pH 7, adsorption dose of 20 mg, and temperature of 303 K. At optimized conditions, the adsorption capacity for ETR and ETA was 52.4 mg/g and 109.05 mg/g, respectively, and the removal efficiency was 81.6% and 93.8%. Both Langmuir and pseudo-second-order reactions matched the experimental results perfectly.