Removal Of M-xylene And Carbon Disulfide By Absorption Combined With Electrochemical Oxidation By Ti/RuO₂ Anode

Volatile organic compounds?VOCs?and odorous gases are important precursors of atmospheric pollution which includes haze and photochemical smog.M-xylene and carbon disulfide?CS₂?are the typical representatives of VOCs and odour gases,respectively.This paper investigated that the treatment of m-xylene and CS₂ from gas stream by absorption combined with electrochemical oxidation.The influences of the type of electrolyte,the concentration of NaCl,current density and pH on the result of experiment were discussed.The electrochemical reactor used in the experiment was a wire-tubular reactor with a stainless steel wall as the cathode and a titanium rod??10mm×350 mm?coated with RuO₂?Ti/RuO₂?as the anode.Experimental results found that the removal of m-xylene of inlet concentration 400 mg/m³ was 55%in 0.3 mol/L NaCl solution?pH=2?by a current density of 26 mA/cm² applied to the reactor.The removal of CS₂ of inlet concentration 3000 mg/m³ was 45%in 0.05mol/L NaCl solution by a current density of 39 mA/cm² applied to the reactor.It was found that the removals of m-xylene and CS₂ were higher in NaCl solution than that in Na₂SO₄solution,which is attributed to the indirect oxidation by active chlorine generated by electrochemical reaction on Ti/RuO₂ anode.It was also found that the removals of m-xylene and CS₂ were gradually increased with the increase of concentration of NaCl.With the increase of the current density with a certain range,the removals of m-xylene and CS₂ were also increased gradually.However,with the further increase of applied current density,the oxygen evolution increased,which might cause the decrease of energy efficiency.In the presence of chloride ions,it is confirmed that oxidation of both m-xylene and CS₂ increased in acid environment.The removal of CS₂ was increased by adding activated carbon to absorbent due to the formation of a three-dimensional electrode.M-xylene is converted to chlorinated m-xylene and dimethylphenol by electrochemical oxidation by GC-MS analysis.CS₂ is mainly degraded to sulfate and CO₂ by electrochemical oxidation by IC and FT-IR analysis.According to the experiment result,the actual treatment of VOCs by absorption combined with electrochemical oxidation was designed and analyzed.