Fabrication of N-doping activated carbon (NDAC) from saw dust/ZnCl2 for Acid Brown 14 dye removal from water

Abstract

Abstract Nitrogen-doped activated carbon (NDAC) was prepared from saw dust/zinc chloride (2:1) by heating under the flow of ammonia gas at 600 °C, 700 °C, and 800 °C and tested for Acid Brown 14 (AB14) dye adsorption from aquatic solution. The fabricated N-doping activated carbons (NDACs) were characterized by FTIR, TGA, DTA, BET, BJH, MP, t-plot, SEM, EDX, and XRD. The NDACs fabricated at 600 °C, 700 °C, and 800 °C were tested for their capacity to adsorb AB14 dye from water. The nitrogen mass % content in the prepared activated carbon ranged between 17.99 and 21.43%. The NDAC prepared at 600 °C specific surface area, monolayer volume, and mesoporous mean pore diameter were 281.84 m2/g, 64.753 cm3/g, and 2.352 nm, respectively. The NDAC synthesized at 600 °C with a 21.12% nitrogen content was found to be the best one to remove AB14 dye from water and named as NDAC600. The impact of solution pH, initial concentration, and adsorption dosage on the adsorption of AB14 dye by NDAC600 was tested. The adsorption of AB14 dye by NDAC600 was found to be pH dependent, with the optimal elimination of being obtained at pH value 1.5 with a removal efficiency of 89.03%. The adsorption of AB14 dye is attributed to the electrostatic contact between the NDAC600 positively charged sites and the anionic AB14 dye. The AB14 dye adsorption was perfectly designated by using both pseudo-second-order (PSO) and Temkin adsorption kinetic models. The maximum adsorption capacity (Qm) was 909.09 mg/g; moreover, the adsorption process was monolayer sorption of AB14 dye to NDAC600. NDAC600 had proven itself as an effective, available, and green adsorbent for the adsorption of AB14 dye from water and may be applicable to other hazardous pollutants.