Preparation and characterization of low-cost nano-particle material using pomegranate peels for brilliant green removal.

A low-cost nano-particle material was successfully prepared using waste pomegranate peels. Batch adsorption experiments were carried out to investigate the effect of different operating conditions on the removal of brilliant green (BG) dye from an aqueous solution. SEM images of pomegranate peels nano-particles (PPNP) declared roughness of the surfaces and TEM images indicated a spheroid shape with an average particle size of 37 nm. The specific surface area of the PPNP was 354.46 m2/g and the particle size had a mean diameter of 613.4 nm. The active nano-particle suspension showed a net negative charge (-29 mV) at natural pH. The XRD pattern of PPNP displayed an average crystallite size of 13.50 nm and EDS analysis shows that the PPNP consists of 83% carbon. The experimental work showed that the removal of BG had optimum removal efficiency at 20 min, 0.3 g adsorbent mass, 25 °C, and pH 8. The kinetic data can be described well with the pseudo-second-order model and the isotherm data was found to fit the Dubinin model. The thermodynamic study proved that BG adsorption on PPNP was physisorption (ΔG = -5.949 kJ/mol) and spontaneous at low temperature (ΔH = -17.193 kJ/mol, ΔS = -0.0382 kJ/mol. k)This study used an agriculture waste (pomegranate peels) to prepare an environmentally friendly and low-cost adsorbent within the nano-scale by thermal activation. The nano-particles prepared were shown to be a promising adsorbent, demonstrating high surface area and well-developed porosity. The prepared adsorbent will have a great impact on wastewater treatment technology and possible applications at a large scale.

Experimental study on the adsorption of Cr+6 and Ni+2 from aqueous solution using low-cost natural material.

The adsorption behavior of Chromium (Cr)(VI) and Nickel (Ni)(II) from aqueous solution onto date pits (DPs) was investigated as a function of initial concentration (5-100 mg/L), contact time (0-70 min), adsorbent dose (2-20 g/L), pH (1-9), and temperature (25-95[Formula: see text] Equilibrium took place after 45 and 55 min for Cr(VI) and Ni(II), respectively. The removal efficiency reached 100% and 95% for Cr(VI) and Ni(II), respectively, at optimal conditions. Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) analyses were performed to characterize the adsorbent. The Langmuir, Freundlich, Tempkin, and Dubinin-Radushkevich (D-R) models were applied to describe the equilibrium isotherms. The values of the free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) were 34.599 kJ/mol, 17.5736 kJ/mol K, and -51.58 kJ/mol K, respectively, at pH 3 for Cr(VI) and -25.283 kJ/mol, -14.8525 kJ/mol K, and 31.31 kJ/mol K, respectively, at pH 6 for Ni(II). Kinetics of the adsorption was analyzed. The pseudo-first-order was suitable for Cr(VI) at R2 = 0.9977, and the pseudo-second-order model was suitable for the Ni(II) at R2 = 0.999. The maximum adsorption capacities were 110.02 mg Cr(VI)/g and 10.1 mg Ni(II)/g. A single-stage batch adsorber was designed for the adsorption of Cr(VI) and Ni(II) by DP based on the optimum isotherm.