| Iodinated by-products?I-DBPS?is a new type of highly toxic disinfection by-product found in the disinfection process of drinking water,I-DBPS have gained increasingly attentions recent years for their much more genotoxic and cytotoxic than their chlorinated and brominated analogues effects on human beings and natural lives,according to previous studies.I-ubiquitously exists in natural environment,which contributes a lot to the formation of iodinated products during regular water treatment oxidation processes.Persulfate advanced oxidation technology has received great attentions in industrial synthesis processes,as well as the sewage disposal and soil remediation.Due to its weak oxidation capacity,PDS is commonly activated in water treatment processes.In the water treatment process,Fe???are the most widely studied persulfate activators,Sulfate radicals produced from Fe???activated peroxydisulfate?PDS?can oxidize iodide?I-?to RIS,which is readily converted into iodide by-products?I-DBPs?in the presence of natural organic matter.This work investigates the transformation of iodide?I-?by Fe???activated peroxydisulfate?PDS?,and the influence factors on the I-DBPs are investigated.Meanwhile,the oxidation of iodide by the thermally activated PDS was investigated.The presence of Fe?IV?in the system was determined by TMSO and the reaction relationship in the experiment was resolved.Effects of different influencing factors on the transformation of iodide by Fe???activated peroxydisulfate?PDS?were investigated.The conversion rate of iodide decreased gradually with increasing pH from 3 to 10.At pH 3,the conversion rate of iodide was 73.5%.When the concentration of PDS is in the range of 20?M-120?M,the conversion rate of iodide first increases and then tends to be stable.At the PDS concentration of 100?M,the conversion rate of iodide is max.When the ratio of Fe???/PDS reaches 4:5,the conversion rate of I-is up to 56%.SO4·-exposures in the experimental system was studied,and the concentration of Fe???in the experiment and the reaction mechanism in the experimental system were analyzed.This work investigates the effect of HA on the iodide conversion by the Fe???activated PDS process.Under acidic conditions,the conversion rate of I-is high,and the yield of I-DBPs is also high.The yield of I-DBPs is low under alkaline conditions,but the conversion rate of I-is also small.The effects of the concentration of PDS and Fe???/PDS,which affect the formation of I-DBPs,were studied.The results show that the concentration of PDS was increased,and the concentration of I-DBPs was increased and then stabilized.The results were best when Fe???/PDS was 4:5.In the experiment,the relationship between the formation of I-DBPs and the concentration of RIS was analyzed.The conversion rate of the transformation of I-by Fe???activated peroxydisulfate?PDS?is low,Therefore,the thermal activation was applied in the experiment.It is found that when Fe???and thermal activation are applied simultaneously,it can not only reduce the temperature of thermal activation alone,but also increase the conversion rate of I-.In the experiment,the factors affecting the oxidation of I-by Fe???and thermal activated PDS were studied.It is found that the I-can be completely converted to IO3-when pH reached 3,4,and 5.At different concentrations of PDS,the conversion rate of I-increases compared to the individual the Fe???activated PDS,When the Fe???/PDS reached to 4:5,I-were all converted to IO3-,The formation of I-DBPs was studied in the part.74%of I-was converted to IO3-and 26%of I-were converted to I-DBPs,The thermal activated PDS need to adjust the temperature to80?can completely oxidate I-,Fe???and thermal activation PDS just adjust to 60?. |
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