Adsorptive removal of malachite green from aqueous solution using modified peanut shell

The aim of the present work is to investigate the adsorptive removal of malachite green (MG) from aqueous solution using modified peanut shell (MPS). The MPS characterizations were investigated using scanning electron microscopy (SEM) and Fourier transform infrared spectra (FTIR). The effect of various factors, such as initial dye concentration, contact time, pH, temperature, and dosage, were investigated during a series of batch adsorption experiments. The SEM and FTIR showed that some components of raw peanut shell (RPS) had been removed during the chemical modification, and many cavities of various dimensions were clearly evident on the surface of MPS. Adsorption experiments showed that MG adsorption uptake was increased with an increase in initial concentration, contact time, solution temperature, and adsorbent dosage. Furthermore, neutral pH was optimum for the removal of MG. The adsorption of MG onto MPS agreed well with the nonlinear Langmuir and Sips isotherm models. The monolayer capacity (q(max)) was 32.73 or 35.85mg/g as calculated from Langmuir or Sips isotherm models, respectively. The adsorption kinetic studies showed that the adsorption process followed the pseudo-second-order kinetic model with a multi-step diffusion process.