| Fluoride,as a trace element in human body,can promote human health with moderate intake,while excessive intake can seriously harm human body.Excess fluoride in natural rivers poses a serious threat to human health,and the development of new and efficient fluoride removal technologies and materials has attracted much attention.At the same time,based on technical and economic considerations,the use of low-cost solid waste materials to prepare adsorption substrates for the treatment of low-concentration fluoridated water also has some research value.In this paper,several common solid waste materials and biomass materials were selected for adsorption experiments on fluoridated surface water,and runoff simulations were performed using the SWAT model for small watersheds with high fluoride content in Ningxia Hui Autonomous Region,and the following results were obtained:(1)The adsorption pre-experiments of selected materials showed that cement-based construction waste and fruit shell biochar had certain adsorption capacity for fluoride ions in water.Some of the materials could not be used as adsorption substrates because they contained a large amount of fluoride,so the influence of the fluoride content of the materials should be considered when selecting the adsorption materials.(2)Apricot shell biochar,which has relatively high fluoride removal capacity among various materials,was selected as the main object of study,and activated alumina and activated apatite filter media were used as comparison objects.The optimum test conditions for the treatment of 50ml of fluoridated water with 2.54mg/L and pH 7.5 with apricot shell biochar were determined by static singlefactor adsorption test at room temperature of 25℃:particle size of 200 mesh,dosage of 200mg,reaction time of 40min,and oscillation speed of 150r/min.The adsorption reaction process of fluoride ions by apricot shell activated carbon satisfies the quasi-secondary kinetic model,and the adsorption is consistent with the Freundlich model.(3)The SWAT hydrological model was used to simulate the area upstream of the monitoring section at the Huangjia River hydrological station in the Xiaohe River basin,and the results showed that the SWAT model has good applicability and simulation effect for this basin.The model simulation effect was evaluated using the decision coefficient and efficiency coefficient with the rate period from January to June 2020 and the validation period from July to December 2020,and the results showed that the R2 value was 0.75 and the NS value was 0.79 during the rate period.The theoretical adsorption capacity in the watershed was calculated using apricot shell activated carbon as the adsorption matrix for interception and slow release bioengineering,and the results showed that if ecological dams were deployed at the source and upstream of the runoff in the watershed,0.2 t to 11.51 t of soluble fluoride could be adsorbed annually,and if replicated in other areas with high soil fluoride The results show that if the ecological dams are deployed at the source and upper runoff levels in the watershed,they can adsorb 0.2t to 11.51t of soluble fluoride per year. |
PDF Full Text Request