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.

Adsorption of cationic dye from aqueous solutions by date pits: Equilibrium, kinetic, thermodynamic studies, and batch adsorber design.

The retention profile of methylene blue from aqueous solutions onto the solid adsorbent date pits has been investigated in a batch system. The characterization and adsorption efficiency for methylene blue was evaluated using date pits. Fourier Transform Infra-Red, Scanning Electron Microscope, Brunauer-Emmett-Teller analysis were performed to determine the characteristics of the material. The effect of contact time, initial dye concentration, adsorbent dosage, temperature, and solution pH were investigated. The adsorption was found to increase with increasing time, decreasing concentration of dye, decreasing temperature and increasing dosage up to equilibrium values which was 20 min, 25°C, and 0.1 g adsorbent, respectively. The adsorption was favorable at high and low pH (pH 3, pH 7). The adsorption equilibrium data were best fitted by Freundlich isotherm. The adsorption kinetics was found to follow the pseudo second order kinetic model. Thermodynamic parameters such as free energy, enthalpy, and entropy were calculated and found to be -4.6 kJ/mole, -7.9 kJ/mole, and -11.8 kJ/mole, respectively. The thermodynamic parameters of the uptake of methylene blue onto the date pits indicated that, the process is exothermic and proceeds spontaneously at low temperature. A single stage batch adsorber was designed for adsorption of methylene blue by Date Pits based on optimum isotherm.