Preparation Of Adsorbent By CTMAB/BS-12 Modified Dianchi Sediment And Its Adsorption To Cr(Ⅵ)

The dredged sediments of Dianchi Lake require a large area of storage yards,and they are placed around Dianchi Lake for a long time,which is likely to cause secondary environmental pollution problems such as surface water and groundwater.Therefore,the reduction and recycling of sediments of Dianchi Lake is very necessary.The bottom mud of Dianchi Lake has a certain void structure and has the characteristics of an adsorbent,and the sediments of Dianchi Lake is negatively charged and has an electrostatic adsorption effect on metal ions;at the same time,it contains humus can complex with metal ions to adsorb heavy metal ions.so the sediments of Dianchi Lake is used as an adsorbent for adsorbing heavy metal ions Cr（Ⅵ）.Chromium-containing wastewater is difficult to handle,not only pollutes the water body,but also directly affects the human body through the food chain to cause disease.In this paper,the sediments of Dianchi Lake was used as the research object.The sediments of Dianchi Lake was treated with cationic surfactant cetyltrimethylammonium bromide（CTMAB）and zwitterionic surfactant dodecyl dimethyl betaine（BS-12）.The mud is modified to prepare an adsorbent,and the influencing factors and efficiency of the adsorption treatment of Cr（Ⅵ）wastewater are studied:1)Preparation and characterization of modified Dianchi sedimentsThe adsorbent was prepared by using the sediments of Dianchi Lake as a carrier.Studies have shown that when the CTMAB（c=8 mg/L）solution and the sediments of Dianchi Lake are mixed in a ratio of 50m L:10mg(remember Dianchi bottom mud _CTMAB),The Cr（Ⅵ）removal rate is 93.9%.When the ratio of BS-12（c=6 mg/L）solution and Dianchi bottom mud is 50 m L:10 mg,the adsorbent(remember Dianchi bottom mud _BS-12),The Cr（Ⅵ）removal rate reached95.3%.At the same time,BET,SEM,XRD,FTIR and Zeta potential characterization analysis of Dianchi bottom mud,Dianchi bottom mud _CTMABand Dianchi bottom mud _BS-12.The results show that Dianchi bottom mud _CTMABand Dianchi bottom mud _BS-12have a larger specific surface area(107.49 m²·g^-1,129.86 m²·g^-1);and the poles of Dianchi bottom mud _CTMABand Dianchi bottom mud _BS-12have greater hydrophilicity and has more hydrophilic group-OH,;the carbon content of Dianchi bottom mud _CTMABand Dianchi bottom mud _BS-12are higher.2)Study on the factors affecting the adsorption of Cr（Ⅵ）by the modified Dianchi sedimentsThe adsorption experiment shows that when the dosage of the adsorbent is 0.2 g/100 m L,the adsorption time is 1440 min,the initial Cr（Ⅵ）concentration is 40 mg/L,the temperature is30℃,and the p H of the Dianchi sediment system is 7.When the p H of Dianchi bottom mud _CTMABsystem is 6,and the p H of Dianchi bottom mud _BS-12system is 13,the removal effect of Dianchi sediment,Dianchi bottom mud _CTMABand Dianchi bottom mud _BS-12on Cr（Ⅵ）is better（removal rate respectively are 40.1%,87.6%and 92.4%）,the removal rate of Cr（Ⅵ）by Dianchi bottom mud _CTMABand Dianchi bottom mud _BS-12is 2-3 times that of Dianchi sediment;3)Study on the adsorption mechanism of modified Dianchi sediments to Cr（Ⅵ）The adsorption of Cr（Ⅵ）by Dianchi bottom mud _CTMABand Dianchi bottom mud _BS-12conforms to the Langmuir model and pseudo-second-order kinetic equation.The adsorption mechanism is mainly surface adsorption and electrostatic adsorption.The adsorption process is a spontaneous endothermic adsorption reaction.The heat of adsorption is close to the sum of the heat of adsorption generated by the van der Waals force and hydrogen bonding force during the adsorption process.4)Research on desorption regeneration experiment and application research on actual wastewater treatmentThe regenerative adsorption experiments show that Cr（VI）forms stable adsorption on Dianchi bottom mud _CTMABand Dianchi bottom mud _BS-12,and the regenerative adsorption effect is not ideal.Under the best experimental conditions,Dianchi bottom mud _CTMABand Dianchi bottom mud _BS-12adsorbed chromium-containing wastewater from electroplating plant.The removal rate of Dianchi bottom mud _CTMABwas 26.9%,and Dianchi bottom mud _BS-12The removal rate of electroplating chromium-containing wastewater is 31.2%,and it also has a certain removal effect on other heavy metal ions(such as Cu^2+,Ni²⁺and Zn²⁺)in electroplating chromium-containing wastewater,and the removal rate is about 20%;It is feasible to use Dianchi bottom mud _CTMABand Dianchi bottom mud _BS-12to prepare adsorbents for adsorbing heavy metal ions Cr（Ⅵ）,without causing secondary pollution problems,which can give new ideas for the recycling of Dianchi sediments.