Molecular Sieve 4A Assisted Peroxymonosulfate Activation Forhumic Acid Degradation as a Model of Persistent Organic Matter in Landfill Leachate
Landfill leachate is multivariate wastewater, usually has a large number of bio refractory organic compounds, which hamper the performance of traditional biological and physiochemical treatment processes. Advanced oxidation process based free radicals generationis an expedient process for bio refractory organic degradation, widely applied to destruct their bonds and mitigate their adverse effect onthe aquatic environment and human health. Sulfate radicals based advanced oxidation process has gained much attention recently, in which the higher oxidation potential of sulfate radicals has successfully achieved higher degradation for various kinds of recalcitrant compounds. Many kinds of chemical oxidants are used to release the sulfate radicals in the presence of an activator, however, acquiring a stable and eco-friendly activator is still challenging work. Herein, in this study, the synergetic activation of peroxymonosulfate (PMS) using molecular sieve 4A zeolite (catalyst) for bio-refractory organic degradation represented by a model humic acid target pollutant is not well known. The objective of this study was to assess the performance of humic acid degradation using molecular sieve 4A-activated peroxymonosulfate (PMS) and to find the optimal operating conditions. The effect of water pH (pH 3.0; 5.0; 7.0; 9 and 11), peroxymonosulfate dose (0.50; 1.0; 2.0 and 4.0 gm/L), molecular sieve 4A dose (1.0; 2.0; 3.0 and 4.0 gm/l) and reaction time (5.0; 10; 20; 40 and 60 minutes) were proposed, to identify the best performance and optimal operating conditions. The rate of humic acid degradation was determined based on the quantification of total organic carbon (TOC), UV254, UV280, and UV400.The highest removal efficiency of humic acid (93.91%) was obtained at pH (7.0), PMS dose (4 gm/L), catalyst (molecular sieve 4A) dose (2 gm/L), and reaction time of 60 minutes. While the decrease of PMS dose and the increase of catalyst dose have decreased the degradation of humic acid performance. The obtained results using an eco-friendly catalyst (molecular sieve 4A)-activated PMSis a promising method for the degradation of humic acid, which would provide a new sight for practical application with cost-effective benefits.