Ultrasonic-assisted synthesis of Populus alba activated carbon for water defluorination: Application for real wastewater

Efficient activated carbon was ultrasonically synthesized from the Populus alba tree, and fluoride ions were removed from samples of synthetic and real wastewaters. The effects of various parameters including pH (2-10), time (5-180 min), contaminant concentration (10-100 mg/L), sorbent dose (1-7 g/L), and co-existing ions on the fluoride removal using Populus alba activated carbon (PAAC) were revealed. The physico-chemical characteristics of PAAC were determined using SEM, FTIR, BET, XRD, and EDX mapping. The specific surface area and pore volume of the mesoporous PAAC were obtained as 707.39m(2)/g and 0.40 m(3)/g. The study found that the maximum removal efficiency of fluoride (93.37%) occurred under the fluoride concentration of 10 mg/L, PAAC of 4 g/L, pH of 6, and contact time of 100 min. The isotherms and kinetics data could be suitably reflected by the Freundlich and the pseudo-second-order kinetic models, respectively. Langmuir maximum monolayer adsorption capacity of the ultrasonic-assisted PAAC was measured as 77.12mg/g. Sorption of fluoride ions onto PAAC is feasible and an exothermic process. According to the field test, PAAC can significantly remove fluoride and other pollutants like BOD5, COD, Ni, Co, and Pb from glass and shipyard wastewater samples.