Lead and cadmium removal by a low-cost adsorbent-banana peel

Water pollution because of inorganic contaminants is a serious problem due to the acute toxicities and carcinogenic nature of pollutants. Recently, much attention has been focused on using natural and low-cost adsorbents, especially food residues, for removing toxic metal ions. Batch removal of nickel (Ni(II)), lead (Pb(II)), and cadmium (Cd(II)) from aqueous solution using a natural adsorbent is described in this study. Effects of various parameters on adsorption capacities such as pH, adsorbent dose, and stirring time were investigated by batch experiments. The maximum adsorption capacities for Ni(II), Pb(II), and Cd(II) ions were 1.6 mg g-1, 125 mg g-1, and 84 mg g-1, respectively. Characterization of the surface modification was performed with FTIR measurements. FTIR spectra showed that chemisorption takes place at the surface of the adsorbent. The Freundlich and Langmuir adsorption isotherms were used to evaluate the equilibrium data. The characteristic parameters for each isotherm were determined. The Langmuir and Freundlich isotherm provided the best correlation for Ni(II), Cd(II), and Pb(II) using banana peel

Adsorption of Bisphenol A from aqueous solutions by Pleurotus eryngii immobilized on Amberlite XAD-4 using as a new adsorbent

The adsorption of bisphenol A (BPA) in a fixed-bed column was evaluated in this work. Fungus Pleurotus eryngii isolated from Tunceli (Turkey) immobilized on XAD-4 resin was used as an adsorbent for decontamination of BPA from aqueous solutions. The extent of BPA removal capacity was evaluated as a function of parameters such as pH, volume of the sample, and column bed height. Adsorption isotherms of BPA on immobilized P. eryngii were determined and correlated with common isotherm equations such as Langmuir and Freundlich models. The mechanism of adsorption of BPA was analyzed preadsorption (XAD-4 + fungus) and postadsorption (XAD-4 + fungus + BPA) using fourier transform infrared spectroscopy. The results show that adsorption ability of BPA by immobilized P. eryngii is possible and this system yields the best degree of BPA removal (90%) at pH 11 for an initial load of 120 mg L−1. Therefore, this material can be used as a very effective adsorbent for BPA decontamination in aqueous solutions

Optimization of Cadmium Removal From Water by Hydroxyapatite Using Experimental Design Methodology

The presence of cadmium in water is a serious threat to the environment. The removal of cadmium using hydroxyapatite as an adsorbent was studied in an aqueous system. Hydroxyapatite was prepared to process the adsorption of cadmium from aqueous solution. Experimental design methodology and response surface methodology (RSM) with a quadratic model associated with central composite design was used to optimize the pH, initial heavy metal concentration, final volume, and adsorbent dosage for the removal of cadmium. Analysis of variance identified significant factors on each parameter. RSM indicated that a pH of 8.5, a sample volume of 166 mL, an adsorbent of dosage 0.57 g, and a contact time of 82 min were optimal for the adsorption of Cd(II). Under these conditions, the removal of Cd(II) was 895 mg g−1