Leaching of Ibute-Nze kaolin iron-oxide impurity with oxalic acid process optimization of dissolution conditions using response surface methodology

The goal of this research was to remove iron oxide from Ibute-Nze kaolin by dissolving the clay mineral in an aqueous oxalic acid solution and optimizing the process. The chemical composition of the raw and modified clay was determined using x-ray fluorescence, and the morphology of the solid sample was determined using a scanning electron microscope. The best conditions for the oxalic acid leaching of iron-oxides impurity from Ibute-Nze kaolin were determined using response surface methodology based on Box-Behnken design. The studies were carried out within the following process parameter ranges: 40–90 leaching temperature; 0.075-0.355mm particle size; 1–6 mol/dm3 acid concentration; 0.02–0.12 g/cm3 kaolin sample to acid ratio and 30-240 min contact time. The characterization revealed that Ibute-Nze clay is kaolinitic in nature and calcination at 750 opens more pores for its leaching. According to the analysis of variance, a second-order polynomial regression equation provided the best fitting for the experimental data. The predicted and experimental response values were shown to be correlated (R2 = 0.9276) in the experimental runs. The following were found to be the best conditions for the leaching process variables: 83.2051 leaching temperature, 0.0827mm particle size, 3.6179mol/dm3 acid concentration; 0.0287g/cm3 kaolin to acid ratio and 217.932min reaction time. The chemical leaching process was 92.6035 per cent under these conditions, which made the clay good for industrial applications

Canarium schweinfurthii stone-derived biochar: A promising adsorbent for crystal violet dye removal

In this study, the effectiveness of C. schweinfurthii biochar (CSSB) for the adsorption of aqueous crystal violet dye (CVD) was investigated. Batch mode experiments were conducted to examine the influence of different process variables on the dye adsorption capacity of the CSSB. The surface chemistry and morphology of the adsorbent were elucidated using the Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy/energy dispersion X-ray (SEM/EDX), respectively. At optimum adsorption conditions (50 mg/L adsorbate concentration, 303 K and 35 min), a maximum removal efficiency of 90.04% was achieved. The experimental equilibrium and kinetic data were best fit to the Freundlich isotherm and Elovich kinetics models, respectively. The thermodynamic evaluation showed average Gibbs free energy (ΔGo), entropy change (ΔSo) and enthalpy change, (ΔHo) values of −1647.18 KJ/mol, −58.69 KJ/mol K and −173.10 KJ/mol, respectively. These thermodynamic data demonstrated that CVD adsorption onto CSSB was favourable, spontaneous, and exothermic. Any doubts about the adsorbent's economic viability were allayed by its projected cost of 0.0003 USSD/g per gram of adsorbate. Thus, according to the experimental results, the CSSB is considered an economical, effective, and environmentally friendly adsorbent for aqueous CVD adsorption