The Study On The Purification Process And Working Mechanism Of Low Concentration Sulfur Dioxide By Bamboo Charcoal In Cultural Relics Conservation Environment

SO2 not only damages the cultural relics greatly by itself,but also enhances the corrosion of cultural relics together with other aerosol pollutants even though the SO2 concentration is very low in the indoor environment.Therefore it must be paid special attention to air purification technology for preserving the heritage.This thesis focused on the sulfur dioxide purification in the micro-environment to preserve cultural relics by bamboo charcoal.SO2 purification efficiency was studied under different operation conditions,such as charcoal size,charcoal amount,inlet concentration or residence time.Through the fitting analysis of SO2 adsorption curve,adsorption capacity of bamboo charcoal was obtained and the mathematical model was established to calculate the life span of bamboo charcoal.Original bamboo charcoals were modified by means of ultrasound and microwave in order to further increase the adsorption efficiency.The charcoal surface characteristics,including pore nature.the ratio of carbon and oxygen content,were measured by SEM and EDS analysis and compared before and after modification.The SO2 adsorption efficiency on charcoal were investigated in the presence of water,organic acids or NOx respectively.The correlation between functional groups and adsorption mechanism were discussed by XPS,FTIR and Boehm titration.The air purifer and humidity controller were combined to study their interaction.Results indicated that:the highest purification efficiency,nearly 100% was achieved in the case of 11 grams charcoal,the inlet flow rate of 1L/min.The modification by ultrasonic and microwave treatment can increase the purification efficiency to be 98% for 52 ppb SO2 when 1 gram bamboo charcoal was used.Furthermore,the microwave method acts slightly better than ultrasonic modification.The best SO2 removal rate was found when relative humidity ranged between 40% and 60%,SO2 purification efficiency was not significantly impacted by low concentrations NOx or organic acids.The functional groups of C-O- and C=O in the charcoal surface had great relevance with SO2 purification.