Nanoporous carbon adsorbents for water purification from phenol compounds

The purpose of the work is to compare the adsorption of phenol (P) and 4-chlorophenol (CP) by activated carbons (ACs) from coals and coking semi-products (CSPs). The ACs with specific surface SDFT = 1009–1547 m2/g were prepared by alkaline activation at a KOH/substrate ratio of 1 g/g (800 °С, 1 h). The characteristics of ACs porosity were calculated by nitrogen adsorption – desorption isotherms (–196 °С). The adsorption capacities for P (АP) and CP (АCP) were measured at 25 °C, АC dosage – 1 g/l and concentration 5 mmol/l. The specific adsorption capacities (АP(S), АCP(S)) and the initial adsorption rates of P (VP) and CP (VCP) for the first 5 minutes of adsorption were also determined. The coal and CSP type were established to determine the porosity and adsorption activity of ACs. Adsorption kinetics obeys the pseudo-second order model (R2 ≤ 0.996). The maximum capacities are AP(m) = 1.52–3.11 mmol/g and ACP(m) = 1.63–3.87 mmol/g. Initial rates are VP = 0.096–0.258 mmol/g·min and VCP = 0.107–0.607 mmol/g·min. With an SDFT increase, the values of AP(m) and ACP(m) increase linearly. It was found that the specific capacities, which are proportional to the surface concentration of ad