| Permeable concrete has certain water permeability,which can effectively reduce urban waterlogging,supplement groundwater,and improve urban heat island effect.It has been widely used as an ecological permeable pavement.However,due to the limited water purification capacity of permeable concrete,water-soluble organic pollutants in runoff water can directly flow into the groundwater through the pores of the permeable concrete,causing certain pollution to the groundwater.Photocatalytic technology can use sunlight to catalyze the degradation of organic pollutants.Applying it to permeable concrete can effectively remove organic pollutants in runoff water and inhibit runoff pollution.Therefore,the paper self-made non-metallic photocatalyst g-C3N4-N to study its Photocatalytic performance,and loaded it on water-permeable concrete through three methods:soaking,coating,and mixing,to study its photocatalytic degradation of Rh B performance.At the same time,the g-C3N4-N photocatalytic water-permeable concrete was compared with TiO2 and g-C3N4-N/TiO2 composite supported photocatalytic water-permeable concrete to study its photocatalytic degradation of Rh B performance,and the g-C3N4-N/TiO2 composite supported light The basic performance of catalytically permeable concrete and water ecotoxicity were studied.conclusion as below:（1）Taking strength coefficient and water permeability coefficient as assessment indicators,the optimal mix ratio of permeable concrete is determined by orthogonal test:water-binder ratio is 0.30,aggregate ratio is 3.3,and fly ash content is 20%.The 7d compressive strength reaches 16.7MPa,the 28d compressive strength reaches 23.7MPa,and the water permeability coefficient is 4.3mm/s.（2）Using anthranilonitrile and urea as raw materials,a modified graphite phase carbon nitride photocatalyst（g-C3N4-N）with a doping ratio of 1%was prepared by a copolymerization method,with the help of XRD,BET,UV-vis,etc.Determine the structure and performance of g-C3N4-N;and use Rhodamine B as the target pollutant.Under the condition of halogen lamp lighting,study the effect of different p H values,different g-C3N4-N photocatalyst additions,and different rhodamine B concentrations on Rh B The results show that the p H of the solution is 3,the addition amount of g-C3N4-N catalyst is 50mg,and the initial concentration of Rh B solution is 10mg/L,g-C3N4-N photocatalyst has the best photocatalysis for Rh B degradation effect.After 30minutes of dark reaction,the adsorption and removal rate of Rh B by g-C3N4-N reached33.5%,and the degradation rate of Rh B after 120 minutes of light reaction reached97.7%.（3）The self-made modified graphite phase carbon nitride photocatalyst（g-C3N4-N）is combined with the currently widely used titanium dioxide（TiO2）photocatalyst,and g-C3N4-N and TiO2 are supported by three methods of immersion,coating and doping.And g-C3N4-N/TiO2,to study the photocatalytic degradation effect of three kinds of photocatalyst-loaded water-permeable concrete and the stability of photocatalytic water-permeable concrete to the photocatalytic degradation effect.The results showed that the composite photocatalyst g-C3N4-N/TiO2 with a mass ratio of 2:1 was immersed in the permeable concrete at a mass concentration of 0.6%,and the photocatalytic permeable concrete prepared had the best photocatalytic degradation effect.The photocatalytic degradation rate of the photocatalytic concrete reaches 95.86%.After placing the photocatalytic concrete for 3 months,the photocatalytic degradation rate can reach82.54%.（4）In order to verify whether the photocatalytic water-permeable concrete has excellent photocatalytic performance and catalytic stability,it can meet the specification requirements of the strength and water permeability of the water-permeable concrete.The basic performance test of permeable concrete shows that the mechanical properties and water retention of photocatalytic permeable concrete are higher.The 28d compressive strength is increased by 2.25%compared with the control,and the water retention rate is increased by 10.96%compared with the control.Although the water permeability of photocatalytic water-permeable concrete is slightly lower than that of the control,the water permeability of both are greater than 3.5mm/s,which far exceeds the specification requirements（CJJ/T135-2009）;in order to investigate the safety of photocatalytic water-permeable concrete to the water environment Alkali solubility test and zebrafish water ecotoxicity test were carried out.The results showed that the p H value of the photocatalytic permeable concrete soaking liquid was slightly higher in the early stage,but after 14 days,the p H value of the soaking liquid of photocatalytic permeable concrete and ordinary concrete was both Stable at about 9.5,the survival rate of zebrafish in the two soaking liquids of photocatalytic water-permeable concrete and ordinary water-permeable concrete is 87.5%and 85.4%respectively,both exceeding85%,indicating that the photocatalytic water-permeable concrete has no toxic effect on the aquatic environment. |
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