Improvement of dyes degradation using hydrofluoric acid modified biochar as persulfate activator

Feiyue Li,Yue Xie,Yan Wang,Xingjun Fan,Yongbin Cai,Yanyan Mei

doi:10.1080/26395940.2019.1578185

Abstract

ABSTRACTThe hydrofluoric acid modified biochar (HF-BC) was obtained, aiming to improve its performance for activating persulfate (PS) to make acid orange 7 (AO7) degraded in water solution. Results showed that the surface area, micropore volume, carboxyl and phenolic hydroxyl group content of HF-BC increased by 171%, 172%, 23.8% and 50%, respectively, compared to unmodified biochar (BC). The decolorization of AO7 in HF-BC/PS and BC/PS systemwas much more rapid and efficient than that in HF-BC, BC and PS alone system. For the HF-BC/PS system, the AO7 was removal of 99.8%, much higher than that of BC/PS system, probably because of its better surface characteristics. Moreover, for the HF-BC/PS system, it was the higher PS concentration and HF-BC dosage that caused greater AO7 degradation rates, and lower pH was favorable for the degradation. Our results provided a novel method to design biochar as an activator for persulfate-based remediation of dye wastewater.Abbreviations: HF-BC, hydrofluoric acid modified biochar; BC, unmodified biochar; AO7, Acid orange 7; PS, persulfate

Highlights

In recent years, the dyes wastewater pollution, generated from the textile, printing, paper, dyeing as well as food-stuff industry discharge, has become an extrusive environmental issue and drawn more and more concern [1,2,3]
PS has limited capacity to make organics oxidized in an independent manner, it could be activated by transition metal ions, heat or UV-light to produce free radicals SO4− [11,12,13,14,15], with oxidationreducted potential ranging from +2.5 to +3.1 V vs. NHE [16], making a great majority of the organics oxidized and decomposed in water [17]
Compared to BC, the yield of hydrofluoric acid modified biochar (HF-BC) was reduced by 36.4%, the total C and H content of HF-BC increased by 72.9% and 24.7%, respectively

Summary

Introduction

The dyes wastewater pollution, generated from the textile, printing, paper, dyeing as well as food-stuff industry discharge, has become an extrusive environmental issue and drawn more and more concern [1,2,3]. The conventional treatment processes like flocculation and adsorption are inadequate for treatment of azo dye wastewater with high concentration and chroma. They cause solid waste, which creates additional environmental problems that require further treatment [7,8]. With the development of advanced oxidation processes (AOPs), the organic pollutants with toxicity and bio-refractory features in wastewater can be degraded [9]. Activation persulfate (PS) oxidation has been viewed as a burgeoning AOP for degradation of the organic pollutants [10]. PS has limited capacity to make organics oxidized in an independent manner, it could be activated by transition metal ions (mainly iron), heat or UV-light to produce free radicals SO4− [11,12,13,14,15], with oxidationreducted potential ranging from +2.5 to +3.1 V vs. NHE [16], making a great majority of the organics oxidized and decomposed in water [17]

Methods

Results

Conclusion