Research Of Phenolic Wastewater Treatment Technology In The Process Of Biomass Gasification Power

In view of the water pollution problems resulted from biomass gasification, this paper first utilized the H2O2oxidation intensified with ultrasound and the ozonation with the help of biomass char to treat phenolic aqueous solution, and then utilized the biomass char adsorption and the ozonation intensified with biomass char to treat biomass wastewater. The treatment processes were compared, and the coupled process of the ozonation and the biomass char adsorption was more suitable for the treatment of biomass wasterwater.For ultrasonic/CuO/H2O2degradation process, CuO was used as a catalyst and H2O2as the oxidant, ultrasound as intensification techniques. Reinforcement of pulse ultrasonic and continuous ultrasound on phenol degradation reaction was compared, and influence of various factors and kinetics characteristics of phenol degradation by ultrasonic/CuO/H202were investigated. Reinforcement of pulse ultrasound on phenol degradation reaction was better than continuous ultrasound, and pulse ultrasound also can save the energy consumption. Phenol removal ratio can reach97.58% after3h degradation under experimental conditions of temperature30℃, phenol initial concentration100mg·L-1, H2O2dosage0.499mol·(g phenol)-1, CuO dosage1.0g·L-1, ultrasonic frequency20-25kHz, power100W, on-off ratio0.8and pulse ultrasonic modulation frequency0.056Hz. The degradation process conformed to the first order reaction, and the activation energy is43.71kJ·mol-1.For the ozonation process, the effects of reaction time, temperature, pH and flowrate of ozone on phenol concentration and COD were studied, and the intermediate products during the degradation process were determined by GC-MS. Under degradation conditions of temperature85％, pH9, flowrate of ozone0.3L·min-1, concentration of phenol in wastewater decreased from10g-L"1to0.545g·L-1after3h, and COD of wastewater decreased from22980mg-L"1to6720mg·L-1.For the ozonation process intensified with biomass char, the effects of biomass char dosage on phenol concentration and COD were studied. Added5g biomass char into100mL phenol wastewater under degradation conditions of temperature85℃, pH9, flowrate of ozone0.3L·min-1, concentration of phenol in wastewater decreased from10g·L-1to0.445g-L"1after3h, and COD of wastewater decreased from22980mg·L-1to1068mg·L-1. Degradation ratio of phenol in the ozonation process intensified with biomass char was higher than the one in the standalone ozonation process. For the process of biomass char adsorption, adsorption equilibrium curve of organics in a biomass wastewater-biomass char system was determined, and the effects of adsorption time, biomass char dosage on COD removal ratio were studied. The adsorption equilibrium curve could be well described by the Langmuir adsorption isotherm equation, in which the assorption equilibrium constant was8.833×10-5L-mg"1and the maximum adsorption capacity was1.136×106mg·g-1.When20g biomass char was added into100mL wastewater, the system was stirred for10minutes in20℃, COD of wastewater decreased from12496mg·L-1to761mg-L"1and COD removal ratio could reach93.9%.For the ozonation process intensified with biomass char, COD removal ratio was determined and compared with the ones in the other three processes of biomass char adsorption after ozonation, biomass char adsorption and standalone ozonation. The results showed that the degradation ratio of organics in the ozonation process intensified with biomass char was highest, and biomass char dosage was lowest. COD removal ratio was higher than90%when temperature was85℃, biomass char dosage was1g biomass cha·(100mL biomass wastewater)-1, the flowrate of ozone was0.15L·min-1, reaction time was20min.