Preparation Of Modified Excess Activated Sludge-Based Adsorbent And Its Application In Phenol Removal From Coking Wastewater

Excess sludge produced in wastewater treatment plants is one of the major environmental problems that need to be addressed anxiously.Due to the rapid development of industrialization and urbanization,a large amount of sludge is generated from wastewater treatment processes every day.Common sludge management includes landfills,incineration,and land farming.However,various disadvantages and environmental dangers have been accounted for because of the presence of heavy metals,organic pollutants,pathogens,and different contaminants in the sludge.Therefore,to enhance environmental sustainability,a more sustainable and economical alternative way is needed by converting this sludge into a resource.Due to the carbonaceous nature of the waste sludge,this research aimed to convert sludge into a carbonized sludge(CS),activate it(WAS),and then modify it with magnetic particles and chitosan to improve the adsorption capacity of phenol from coking wastewater,and to investigate the effectiveness of sludgebased adsorbents(SBAs).Through carbonization and the use of different modifiers,a series of sludge-based adsorbents were prepared in this study and subjected to scanning electron microscopy(SEM),X-ray diffraction(XRD),Porosity,and Surface Area Analysis,and Fourier transform infrared spectroscopy(FTIR).The results showed that the ideal preparation conditions for sludge-based adsorbents(SBAs)are:carbonization temperature of 500?,KOH activation with a mass ratio of 1:1,FeCl3 magnetic particles with a mass ratio of 1:1,and chitosan solution with a concentration of 0.8%.The data shows that the modification of magnetic particles and chitosan can significantly increase the specific surface area of carbonized sludge from 11.73 m2/g to a maximum of 95.69 m2/g,while KOH activation can increase the porosity of carbonized sludge and increase the hydroxyl functional groups in the material Infrared signal.The 6 prepared adsorbents were used for the adsorption and removal of phenol in wastewater,and the adsorption effect and influencing factors such as contact time,PH,concentration,temperature,dosage,and agitation speed were investigated.The batch adsorption tests showed the great phenol adsorption capacity of the SBAs except for CS.Compared with other SBAs(Sludge Based Adsorbent),MWAS with magnetic modification was found to have an affinity to phenol where the removal efficiency of 54.7%was achieved in 24 hours.WAS was found to have high monolayer adsorption capacity with a monolayer adsorption capacity of 104.24 mg/g and WASC2 exhibited the fast adsorption behavior where 72%of equilibrated adsorptivity were achieved at 160min.Overall adsorption efficiency is MWAS>WAS>MWASC>WASC2>WASC1>CS from the highest to the lowest.Experimental data on phenol adsorption was found to best fit the Langmuir isotherm model.The kinetics of adsorption of phenol was investigated using a pseudo-second-order kinetic model.