Efficient Removal of Nitrobenzene and Its Compounds by Coconut Shell-Derived Activated Carbon

Activated carbon prepared from coconut shell was characterized using SEM/EDS, N2-sorption, XRD analysis, Raman, and FTIR spectroscopy. It was then evaluated in terms of its capacity to adsorb nitrobenzene, a priority pollutant, from water samples with varying pH levels. Initial studies revealed high adsorption capacity; further studies were broadened to include nitrobenzene derivative, dinitrobenzene, as real samples are expected to contain a mixture of these pollutants. The maximum amount of adsorbed adsorbate increased notably with temperature, reaching 12.88 mg g−1 and 42.75 mg g−1 for nitrobenzene and dinitrobenzene, respectively, at 35 °C. Thermodynamic considerations and determined values of ∆G0 and ∆S0 indicated that the adsorption process of both nitrobenzene and dinitrobenzene is spontaneous and ∆H0 value indicated that it is endothermic in the studied temperature range. A study of the simultaneous adsorption of nitrobenzene and dinitrobenzene indicated a higher affinity toward dinitrobenzene. This study pointed out that coconut shell-derived activated carbon holds high potential as an adsorbent for removing nitrobenzene and its derivatives from water samples.