Response surface methodology for optimization of Cd(II) adsorption from wastewaters by fabricated tartaric acid-maize tassel magnetic hybrid sorbent

Abstract

Maize tassels (MT), an agro-based biomass waste was carbonised followed by thermo-chemical modification using tartaric acid. The functionalized activated carbon was further modified to yield a magnetic hybrid composite adsorbent. The adsorbent was characterized using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). The adsorbent was evaluated for its efficiency to remove Cd(II) ions from aqueous solutions through batch adsorption studies following a Central Composite Design. Effects of solution pH, contact time, adsorbent dosage, initial metal concentration and temperature on Cd(II) adsorption were investigated. Optimization of the adsorption process was done using desirability function on the Design Expert V11 software. The desirability function showed that the optimum parameters were pH 5.29, contact time (67.50 min), dosage (0.575 g) and initial concentration (152.50 mg/L). The adsorption process was analysed using kinetic and isotherm models. The kinetics of the adsorption process followed the pseudo-second-order model (lowest sum of square error (SSE) values and correlation coefficients (R2) > 0.999) in addition to the intraparticle diffusion model. The isotherm data were consistent with the Langmuir isotherm as evidenced by the highest correlation coefficient (R2= 0.998). The thermodynamic parameters showed that the process was endothermic and spontaneous in nature. The adsorption capacity of the adsorbent was found to be 188.68 mg/g at 20 ⁰C which is higher than that of the previously reported magnetic maize tassel hybrid (52.05 mg/g). The adsorbent showed good removal efficiency on real effluent samples.

Removal of the toxic cadmium ions from aqueous solutions by zero-valent iron nanoparticles

“…Generally, removal of the pollutants by adsorption is considered one of the most effective processes for wastewater treatment without producing any harmful by-products with the possibility of regenerating both pollutants and adsorbent. Different solid adsorbents were used for the removal of Cd(II) ions from water such as fabricated tartaric acid-maize tassel magnetic hybrid sorbent (Ngwenya et al 2019), Indian saffron-turmeric (Curcuma longa) embedded supermacroporous cryogel disks (Aslıyüce et al 2019), low-cost adsorbents from agricultural production or by-products from industry (Pyrzynska 2019), titanium dioxide nanoparticles (Irshad et al 2019), unmodified and NTA-modified Dendrocalamus strictus charcoal powder (Saini et al 2019), corncob-supported aluminum-manganese binary oxide composite (Zheng et al 2019), and inorganic porous nanocomposites (Ianăşi et al 2019).…”