Optimization of p-Nitroaniline Adsorption from Aqueous Medium by TiO2-Flamboyant Seeds Activated Carbon Composite

Abstract

Titanium (IV) oxide-flamboyant seeds activated carbon (TiO₂-FSAC) composite was studied as a promising adsorbent for p-nitroaniline (p-NA) removal from aqueous media using batch technique. The surface characteristics of the composite were determined by Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, Energy Dispersed X-ray Spectroscopy and Brunauer–Emmett–Teller surface area analysis. The results showed that TiO₂-FSAC is highly porous with a surface area of 601.77 m²/g and pore diameter in the mesoporous region. Box-Behnken design (BBD) under Response Surface Methodology (RSM) was employed for the optimization of four operating parameters: initial p-NA concentration, pH, adsorbent dosage and time. The results revealed that the amount of p-NA adsorbed increased with an increase in initial p-NA concentration, low pH, and low adsorbent dosage and was not affected by time in the investigated range. The correlation between p-NA adsorption by TiO₂-FSAC and the process variables was sufficiently established by the quadratic model with a high R² value (0.973), which is in agreement with adjusted R² (0.945). The optimum amount of p-NA adsorbed was 45.0 mg/g accomplished at C_o = 300 mg/L, pH 2, 0.1 g adsorbent dosage and 362.5 min time.