| In view of the unpleasant smell of the urban black-odorous water,based on the investigation of the main odorous compounds in the black-odorous water,this study prepared biochar with good adsorption performance,and the adsorption study of odorant component were performed.Firstly,the（semi-）volatile components in the black-odorous water were identified by headspace-solid phase microextraction-gas chromatography-mass spectrometry（HS-SPME-GC-MS）,and the main odorous components was determined by t he odor activity value,and their distribution rules and possible sources were discussed.Then,the prepa ration of modified biochar was obtained.Based on the single factor condition selection,the response surface method based on Box-Behnken center combined experimental design was used to optimize the process of biochar preparation,then its removal effect on the main olfactory components in actual black-odorous water was verified;finally,adsorption capacity on designated olfactory components is evaluated through characterization of biochar and analysis of factors affecting adsorption and adsorption kinetics.The main findings are as follows:（1）In the urban black-odorous water,the main olfactory components are dimethyl disulfide（DMDS）,furfural,octanal,citral and phenol（ArOH）,of which DMDS,furfural and octanal in urban black-odorus water have a stable existence.According to RDA analysis,the source of DMDS is mainly due to anaerobic microbial activity in water.Octanal and furfural are naturally present in water.The source of ArOH and citral may be due to external pollution.（2）The order of significant pyrolysis conditions affecting the adsorption capacity of biochar is from high to low:pyrolysis temperature,retention time,phosphoric acid concentration and impregnation ratio;in addition,the interactions between retention time and impregnation ratio,phosphoric acid concentration and impregnation ratio also had a remarkable effect on the adsorption capacity.According to the response surface model,the optimal preparation conditions of phosphoric acid modified biochar were pyrolysis temperature 884.32°C,retention time 82.61 min,phosphoric acid concentration 40.74%,impregnation ratio 1.74,and the predicted maximum iodine value was 1098.94 mg·g-1.The experimental results showed that the actual value and the predicted value are well fitted,and the relative deviation was less than 5%.The adsorption test on the actual water showed that the biochar can effectively remove the main olfactory components obtained in this study;compared with the original biochar,the adsorption capacity of the modified biochar is significantly improved,and the removal rate of ArOH and DMDS can reach more than 80%and has potential application in actual water.（3）The isothermal adsorption curve of biochar on ArOH and DMDS has a high degree of fit to the Langmuir equation,indicating that the adsorption is mainly dominated by monolayer adsorption.The modified biochar has the best theoretical adsorption capacity for the two pollutant components.The maximum adsorption capacity for ArOH theory is 153.30 mg·g-1,and the maximum adsorption capacity for DMDS is 13.51 mg·g-1.Through kinetic analysis,physical adsorption is the main adsorption mode of biochar for two pollutant components,while electrostatic adsorption has certain influence on the adsorption of modified biochar. |
