Abstract
A serious environmental disaster is looming on the horizon due to the indiscriminate release of heavy metals into the soil and wastewater from human industrial practices. In this study, waste mint (WM) was used to remove chromium(VI) from aqueous solution using batch experiments. The adsorbent material (WM) was characterized using scanning electron microscopy coupled with energy dispersive analysis of X-ray spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and thermal gravimetric analysis (TGA). The adsorption parameters optimized were as follows: pH solution (2–11), initial concentration of Cr(VI) (10–50 mg/L), adsorbent dose (0.1–10 g/L), and temperature conditions (298 K, 308 K, and 318 K). The experimental data fitted well to the fractional power kinetic model (0.97≤R2≤ 0.99) and Langmuir isotherm (R2 = 0.984) with a maximum adsorption capacity Qmax = 172.41 mg/g. The thermodynamic parameters for Cr(VI) sorption were also calculated, confirming that the adsorption process was spontaneous and accompanied by an exothermic adsorption (−4.83 ≤ ΔG ≤ −3.22 kJ/mol and ΔH = −28.93 kJ/mol). The Cr(VI) removal percentage was within the range of 41–98%, and the highest removal was noted at pH = 2. The results of the present study suggest that WM is a potential low-cost adsorbent for the removal of chromium(VI) from aqueous solutions.
Highlights
IntroductionE metals of greatest concern are Cr, Mn, Fe, Zn, and Cd, which are widely distributed in the materials that make up the Earth’s surface
Ese effects have been confirmed in animals [6]. is metal is extremely toxic; exposure to high concentration of chromium can cause an epigastric pain, nausea, vomiting, severe diarrhea, and hemorrhage [7]. e maximum level of chromium in drinking water must not exceed 0.05 mg/L [8]
Many investigations have been carried out on the effective removal of heavy metals from solution using natural adsorbents derived from household wastes [12,13,14,15,16]. e purpose of this study is to investigate the possible use of mint waste, a household waste, for the removal of chromium ions from aqueous solution
Summary
E metals of greatest concern are Cr, Mn, Fe, Zn, and Cd, which are widely distributed in the materials that make up the Earth’s surface Among these heavy metals, chromium is found in higher concentrations in wastes from electroplating, paints, dyes, leather tanning, paper mills, and many other industries [3, 4]. Adsorption is generally the most preferred method for the removal of heavy metal ions due to its high efficiency, easy handling, availability of different adsorbents, and cost-effectiveness [11]. Many investigations have been carried out on the effective removal of heavy metals from solution using natural adsorbents derived from household wastes [12,13,14,15,16].
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