Abstract

In the present study, the adsorption of 4-chlrorophenol (4-CP) from aqueous solutions was investigated using activated carbon prepared from milk vetch. Scanning electron microscopy, Brunauer-Emmett-Teller, and Fourier transform infrared were carried out to characterize as-prepared activated carbon. The adsorption process was optimized by response surface methodology based on central composite design. Accordingly, a 4-CP removal of 89.52 was obtained with a reaction time of 49min, initial 4-CP concentration of 56mg/L, adsorbent dosage of 1g/L, and initial pH of 7. Among various operational parameters, the adsorbent dosage (F-value=139.5) produced the largest effect on 4-CP removal (), while initial pH (F-value=0.620) presented the lowest effect. The pseudo-second-order kinetic equation described the process reasonably well (R-2=0.9996). The process followed Langmuir isotherm (R-2=0.9969) with a maximum adsorption capacity of about 87mg/g. For chemical regeneration, during three-stage regeneration runs, the removal efficiency () of 4-CP decreased from 87.45 to 61.15, while, in the case of thermal regeneration, it decreased from 87.45 to 77.68, respectively. Overall, activated carbon derived from milk vetch can be applied as an efficient adsorbent for sequestering 4-CP from aqueous phase with relatively high reusability potential.