Study On The Treatment For Non-Biodegradable Organic Waste Water With Free Radicals

The operation basing on the free radical of the organic waste water of hard degradation is a comparatively high efficient and advanced oxidation technology,and it has received a widespread attention both in domestic and abroad in recent years. The free radicals has many categories(such as hydroxyl free radical, sulfate radical etc.), and it has showed that different activation methods and reaction conditions can also exert a different effect.So from this perspective of view, studying different free radicals and its correspondent activation methods in improving the processing efficiency of organic waste water has become a hotpot in the world.For this paper,it mainly adopts the mode of activation of microwave and ultraviolet,with the common organic pollutant phenol as the processing object,and has analyzed the change of the concentration of phenol and COD before and after the reaction,and later studied the degradation effect of phenol by the reference of different reaction of sulfate free radical, chlorine free radical, and hydroxyl free radical in different conditions. The specific contents are as follows:(1) The operation of the degradation of phenol with sulfate free radical by microwave assisted per-sulfate with activated carbon, the result of the study indicates that when the microwave power is in 560 W, radiation time of 5 minutes, activated carbon dosage of 0.17 g, m (K2S2O8) /m (phenol)=0.5, and the pH=4, the phenol will have a better effect of degradation, the removal rate can be reached 86%,and the COD removal rate is 85%.(2)The operation by lighting hypochlorite with UV,thus generating degraded phenol with chlorine free radical,it can optimizes the processing conditions by changing the reaction conditions:when the ultraviolet radiation period lasts 2 hours, and the adding of the sodium hypochlorite solution with available chlorine of 5 g/L, the m (available chlorine) /m (phenol) =0.7, and pH=12, then it can accelerate the degradation of phenol into the rate of 60%, and the removal rate of COD is 51%.(3)Per-carbonate with the inducing of the UV will produce a strong oxidation of the hydroxyl radical degradation of phenol, by changing the radiation time, sodium carbonate dosage and the pH, we get the optimization of conditions of the degradation phenol:the UV radiation time is 3 hours, the sodium per-carbonate is 0.035 g, the m(reactive oxygen species) /m (phenol)=1,and pH in 4～11, the phenol removal rate can reach above 85%, and the rate of COD can reach above 80%. When we add Fe2+ in the acid condition, and by the investigation of the UV radiation time, the sodium carbonate dosage (with active oxygen meter), the influence of Fe2+ dosage and the pH changes. The result showed that Fe2+ can accelerate the degradation of phenol.Under the radiation of UV light for 20 minutes, m (active oxygen) /m (phenol)=0.6, m (Fe2+) /m (phenol)=0.06, and the pH=5, phenol’s removal rate can reach 85%.(4)By the induction of the microwave, per-carbonate produces hydroxyl free radical thus degenerating phenol.The experimental result has showed that under the condition of the microwave power of 800 W and digests it for 3 minutes,and then by adding sodium per-carbonate, makes the m (reactive oxygen species) /m (phenol)=1.6, and the pH=4～9, then removal rate of phenol reaches more than 85%,and COD of 84%.