Low-rank Coal Activated Coke Pore Structure-Surface Hydrophobicity Dual Regulation And Its Adsorption Treatment Of Organic Wastewater

With the rapid development of our country’s industrial level,a large amount of industrial organic wastewater has also been produced.The adsorption method is an effective method to treat organic wastewater.Our country’s low-rank coal reserves are abundant,and can be used as fuel after adsorbing pollutants,avoiding the problem of difficult disposal of sediment,and providing a better application prospect for its use as an adsorbent.Using Wanli Long Flame Coal(WL)and Zhaotong Lignite(ZT)as raw materials,a series of low-rank coal activated coke(LAC)were prepared through orthogonal experiments.The pore structure of each sample and its adsorption effect on different molecular weight pollutants Carry out research,and select the LAC prepared under the best conditions for physical and chemical analysis.The results show that activation time and activation temperature are significant factors affecting the pore structure of LAC.As the intensity of the activation conditions increases,the pore structure of LAC also shows regular changes.When the activation conditions are lower,the activation The main function is the formation of micropores.As the activation conditions increase,the pores begin to merge,and the micropores gradually merge into mesopores and macropores.LAC with different degrees of pore structure development shows differences in adsorption performance for organics of different molecular weights.LAC with large specific surface area and small pore size can provide more adsorption sites for small molecule pollutants,which is conducive to the adsorption of small molecule substances.LAC with a large pore size can provide a wide material transport channel for the adsorption of macromolecular pollutants,which is more conducive to the adsorption of macromolecular substances.The adsorption capacity of Wanli(Zhaotong)activated coke on four organic pollutants: indole,acid red A,Congo red,and direct light fast blue B2 RL can reach 117.11(135.80),104.24(138.56),239.44(313.94),214.86(183.74))mg/g.Using machine learning methods,five characteristics of LAC are selected to predict the adsorption capacity of LAC.Based on the random forest model,the adsorption capacity of four pollutants can be predicted based on the properties of LAC.And based on the random forest analysis of the five selected factors,the results show that with the change of the molecular weight of the adsorbed substance,the contribution of each factor will also change to a certain extent.Specifically,LAC has a greater effect on the specific surface area and pore volume when adsorbing small molecular pollutants,and has a greater effect on the pore volume and average pore volume when adsorbing macromolecular pollutants.In order to improve the selective adsorption capacity of LAC coke to highly biotoxic and refractory organics,it has been hydrophobically modified.The modified activated coke’s pores are blocked,and the specific surface area and pore volume are reduced to varying degrees.The infrared spectrum shows that the proportion of the OH absorption peak is reduced,which is converted into CO-Si form,and the-CH3 stretching vibration peak appears.Combining the contact angle analysis before and after modification,it can be found that the contact angle of LAC coke is increased after chlorosilane modification.The contact angle of WL and ZT activated coke is increased from 117.8° and 112.6° after chlorosilane modification.127.3° and 139.7°,indicating that the trimethylchlorosilane modifier was successfully grafted to the surface of the activated coke.When investigating the adsorption performance of hydrophobically modified LAC,it was found that in the two-component adsorption experiment,the first two modified LACs had equivalent removal effects on the hydrophilic pollutant phenol and the hydrophobic pollutant indole and DEP,indicating that LAC at this time It is not sensitive to the hydrophobicity of pollutants.After hydrophobically modified LAC,the removal rate of indole and DEP is greatly improved when the removal rate of phenol is not significantly improved.At the same time,when comparing the adsorption performance of LAC to indole before and after the modification,it is found that the adsorption capacity and adsorption efficiency of the modified LAC are significantly improved than before the modification.Analyzing the adsorption thermodynamics and kinetics of LAC before and after modification,the adsorption of indole by LAC is more in line with the Langmuir model,the adsorption of direct light fast blue B2 RL is more in line with the Freundlich model;the adsorption of indole and DEP by modified LAC is more in line with the Langmuir model.The adsorption process of LAC to pollutants before and after modification is more in line with the quasi-second-order adsorption rate equation,and the factors affecting the adsorption rate are different in different stages.The paper has 34 figures,19 tables,and 103 references.