Research On Oxidation Efficiency Of Ozone/Hydroxylamine System

Ozone as a strong oxide has been widely used in treating refractory organic compounds, H2O2, UV, ultrasound had be introduced into the ozone system, which can improve the oxidation ability of ozone and form different advanced oxidatio n technology, Finding a more effective way to improve the ozone oxidation ability has become a focus of study. This paper examines the oxidation ability of ozone / hydroxylamine(O3/HA) system under different reaction conditions, compared with ozone / hydrogen peroxide(O3/H2O2), finally with the aim of dicamba, investigates the removal ability of O3/HA system on the refractory organics in water.The results show that adding an appropriate amount of hydroxylamine can increase ozone removal efficiency on hydroxyl radicalsindicator p CBA and improve the hydroxyl radical(HO?) concentration in solution(calculated from the change of p CBA concentration),The addition of hydroxyl radical scavenger tert-butanol inhibited the reaction on the removal of p CBA, and reduces the concentration of HO?. The removal of p CBA is mainly through the radical pathway rather than direct ozone reaction pathways. When the initial concentration of ozone =20.0μmol/L, p CBA=1.0μmol/L, p H =7.0 ± 0.1, temperature = 20 ± 0.5°C, adding 6μmol/L hydroxylamine, in the reaction starting time HO? concentration is 8.3 times the reaction of ozone alone. Reacted for 30 s resulted, removal rate of p CBA by ozone alone increased from 7.0% to 44.9%. Reacted for 480 s, the removal rate increased from 11.8% to 51.5%.Comparing with O3/H2O2, O3/HA has obvious advantages under acidic conditions. Under the conditions of p H = 3 and p H = 5, In the initial time of reaction, the condition of HO? concentration in the O3 / HA system is 13 times and 2.3 times of O3/H2O2 system,when the reaction time was 480 s, the removal rate of p CBA in the O3/HA system is 11.4% higher and.28.2% higher than that of O3/H2O2. Under neutral conditions O3/HA in the reaction speed is superior to O3/H2O2, at p H = 7, In the initial time of reaction, the concentration of OH in the O3/HA system is 3.3 times of O3/H2O2 system, and at 30 s, O3/HAsystemreached basic balance, the removal rate of p CBA reached 41.2%, while the O3/H2O2 only 14.7%. Under alkaline conditions, O3/HA has no obvious advantages when compared with O3/H2O2.In the underground water experiment, the initial concentration of ozone was 3mg/L, dicamba = 4μmol/L, p H =7.5±0.2, temperature = 20±0.5 °C, under the condition of 8μmol/L hydroxylamine, reaction for 480 s, the removal of dicamba in groundwater by ozone alone increased from 44.2% to 57.2%, increased by 13%.