Removal of quinoline from aqueous solutions by lignite, coking coal and anthracite. Adsorption kinetics

Basing on the concept of circular economy, a novel method of industrial organic wastewater treatment by using adsorption on coal is introduced. Coal is used to adsorb organic pollutants from coking wastewaters. After adsorption, the coal would be used in its original purpose, as its value was not reduced and the pollutant was reused. Through the systemic circulation of coking wastewater zero emissions can be achieved. Lignite, coking coal and anthracite were used as adsorbents in batch experiments. The quinoline removal efficiency of coal adsorption was investigated. Both the coking coal and anthracite exhibited properties well-suited for quinoline adsorption removal. The experimental data were fitted to the pseudo-first- order and pseudo-second-order kinetic equations as well as intraparticle diffusion and Bangham models. An attempt was made to find the rate-limiting step involved in the adsorption processes. Both boundary-layer diffusion and intraparticle diffusion are likely involved in the rate-limiting mechanisms. Effect of pH on coal adsorptions by coking coal was investigated. The process of quinoline adsorption on coal was researched. The coal adsorption method for removing refractory organic pollutants is a great hope for achieving wastewater zero emission for coking plants.