High adsorption capacity of nitrobenzene from aqueous solution using activated carbons prepared from vegetable waste

Abstract

The present study reports the preparation of chemically activated carbons (PAC and ZAC) from apricot stones using phosphoric acid and zinc chloride, respectively. The potential use of the prepared carbons, as adsorbents, and the effect of chemical activation on the surface properties and adsorptive mechanism of nitrobenzene (NB) were investigated. The physicochemical properties of the obtained materials were characterized by Nitrogen adsorption-desorption isotherms, Scanning Electron Microscope, FTIR Spectroscopy, EDX analysis, Boehm titration, and pH of zero charge. The results show that the prepared samples present high apparent surface areas (1,382 and 1,111 m 2 /g for PAC and ZAC, respectively) and pores volumes with the presence of various functional groups. It was found that pseudo-second model was the most suitable for the fitting of the experimental kinetic data and the intraparticle diffusion was not the unique rate-controlling stage. The adsorption isotherms were well described by the Langmuir and the Freundlich models. According to the Langmuir model, the maximum adsorption capacity of PAC and ZAC were about 476.2 and 490.2 mg/g, respectively. The thermodynamic parameters showed the spontaneity, the exothermic nature, and the decrease in the randomness of the adsorption of nitrobenzene. Chemical regeneration showed that the prepared samples could be used for four time desorption-adsorption cycles with good efficiency for NB removal, indicating that the prepared carbons could be used as a low-cost alternative to commercial activated carbon for the removal of nitrobenzene from wastewater.

Adsorption of Eriochrome Black T on Pseudo Boehmite and Gamma Alumina Synthesized from Drinking Water Treatment Sludge: A Waste-to-Recycling Approach

“…The results show that the adsorption rate decreases progressively (K d1 > K d2 > K d3 ) and that the effect of the boundary layer increases progressively (C 1 < C 2 < C 3 ), which is consistent with the evolution of the adsorption rate during the adsorption phase. It can also be seen that the fitted line does not pass through the origin, which further suggests that intraparticle diffusion does not play a major role in controlling the adsorption rate and that several processes act simultaneously during adsorption [30].…”

“…In order to gain a better insight into the influence of temperature on the adsorption process, thermodynamic studies were carried out at different temperatures (20,30,40 • C), keeping the other parameters constant (solution's pH, adsorbent mass 50 mg, dye concentration 50 mg L −1 , contact time 3 h). The mixture was continuously stirred in a double-walled beaker at the set temperature.…”

Comparative study of biochar prepared from cow dung and sewage sludge and its application as an adsorbent for organic pollutants removal in water

“…9 A biochar, is a carbon-rich by-product by pyrolysis of biomass with interest at present, due to its role in carbon sequestration with a structure comparable to the porosity and the surface to the activated carbon of mineral origin. 10 Low-cost adsorbents from natural sources are postulated as an innovation in the use of waste and a cost-effective alternative for their application in wastewater treatment. The use of cow manure is well known for different applications, for example, production of energy by bio-hydrogen, 11 synthesis of electrocatalysts for fuel cells, 12 removal of heavy metals, 13 and fermentation of carboxymethyl cellulase and protease.…”

“…However, commercially available carbons are expensive, so the alternative is to explore the use of agricultural and industrial waste as low‐cost adsorbents 9 . A biochar, is a carbon‐rich by‐product by pyrolysis of biomass with interest at present, due to its role in carbon sequestration with a structure comparable to the porosity and the surface to the activated carbon of mineral origin 10 . Low‐cost adsorbents from natural sources are postulated as an innovation in the use of waste and a cost‐effective alternative for their application in wastewater treatment.…”