Systematic studies on the effect of structural modification of orange peel for remediation of phenol contaminated water

In the present study, orange peel biochar has been utilized as the adsorbent for the removal of phenol from contaminated water. The biochar was prepared by thermal activation process at three different temperature 300, 500 and 700 degrees C and are defined as B300, B500, and B700 respectively. The synthesized biochar has been characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transformation infrared spectroscopy (FTIR), RAMAN spectroscopy, X-ray photoelectron spectroscopy (XPS), and UV-Vis spectroscopy. SEM analysis revealed a highly irregular and porous structure for B700 as compared with others. The parameters such as initial phenol concentration, pH, adsorption dosage, and contact time were optimized, and the maximum adsorption efficiency and capacity of about 99.2% and 31.0 mg/g was achieved for B700 for phenol adsorption. The Branauer-Emmett-Teller (BET) surface area and Berrate-Joyner-Halenda (BJH) pore diameter obtained for B700 were about 67.5 m(2)/g and 3.8 nm. The adsorption of phenol onto the biochar followed Langmuir isotherm showing linear fit with R-2 = 0.99, indicating monolayer adsorption. The kinetic data for adsorption is best fitted for pseudo-second order. The thermodynamic parameters Delta G degrees, Delta H degrees, and Delta S degrees values obtained are negative, which means that the adsorption process is spontaneous and exothermic. The adsorption efficiency of phenol marginally declined from 99.2% to 50.12% after five consecutive reuse cycles. The study shows that the high-temperature activation increased the porosity and number of active sites over the orange peel biochar for efficient adsorption of phenol. Practitioner Points Orange peel is thermally activated at 300, 500, and 700 degrees C for structure modification.Orange peel biochars were characterized for its structure, morphology, functional groups, and adsorption behavior.High-temperature activation improved the adsorption efficiency up to 99.21% due to high porosity.

Automated summary

In this study, orange peel biochar was used as an adsorbent for removing phenol from contaminated water. Three different types of biochar were prepared at different temperatures and characterized using various spectroscopic techniques. The highest adsorption efficiency and capacity were achieved with the biochar activated at 700 degrees C (B700). The adsorption followed Langmuir isotherm and pseudo-second order kinetics. The high-temperature activation increased the porosity and number of active sites, leading to improved adsorption efficiency.