Preparation Of Biochar Activated Carbon And The Research Adsorption Of Phenol Wastewater

Activated carbon (AC) is a kind of porous carbon material, which has greatspecific surface area, developed pore structure, unique functional groups in surface,strong adsorption performance and so on. It has been utilized in medicine, food,chemical industry and environmental protection and all aspects of human life. Inrecent years, especially in the field of water and air treatment, activated carbon hasbeen widely used.This article in which biochar is considered as raw materials and zinc chlorideis used as activator in preparation of activated carbon, examines the impact of massfraction, solid-liquid ratio, activation time and activation temperature on the iodineadsorption value and methylene blue value of biochar activated carbon. The articleis based on single factor experiment, and the method of response surfaceexperiment is adopted. Experimental results of variance analysis indicate that underthe conditions of the zinc chloride method of making biochar activated carbon, theinfluence of mass fraction on the methylene blue and the iodine adsorption value ismost significant, the influence of the activation time is not very important. Massfraction in the interaction of the two factors in solution and the solid-liquid ratiohas most significant influences on the methylene blue value and the iodineadsorption value. The best conditions of making zinc chloride are as follows: themass fraction of zinc chloride solution is41.50%and solid liquid ratio is1:3,activation time is90min, activation temperature is605℃. Under the condition ofthe preparation of active carbon, the methylene blue value is213mg/g, the iodineadsorption value is1020.064mg/g.We use biochar as raw material, KOH as activator for the preparation ofactivated carbon, based on single factor experiment and the response surfaceexperiment design method to examine the alkaline ratio, activation time, activationtemperature on the methylene blue value and the iodine adsorption value of biocharactivated carbon. Experimental results of variance analysis show that under theconditions of the method of KOH for the preparation of biochar activated carbon,activation temperature on the methylene blue value and the iodine adsorption valueis most significant, the influence of activation time on methylene blue value is notvery important, the influence of alkali carbon ratio on the iodine adsorption value is least significant. In the interaction of the two factors, the interaction of theactivation time of methylene blue value and the iodine adsorption value is mostimportant. The best conditions of the method using KOH is: alkali carbon ratio is2.04:1, the activation time is89min, and activation temperature is760℃. Underthose conditions, the methylene blue value is489.6mg/g, and the iodine adsorptionvalue is2094.992mg/g.Physical adsorption apparatus are adopted to measure of activated carbon’snitrogen isothermal adsorption-stripping at77K. We use BET equation, Langmuirequation, BJH and DFT method to calculate activated carbon’s specific surface area,total entrance, the average pore size and pore size distribution under two differentpreparation methods. In the method Zinc chloride, BET and Langmuir, specificsurface area of active carbon is631.185m~2/g,688.201m~2/g, respectively, andtotal entrance is0.3523g/cm~3, average pore diameter was2.233nm; Also, in themethod of KOH, BET and Langmuir, specific surface area of active carbon is1443.987m~2/g,1359.655m~2/g, and total entrance is0.7505g/cm~3, average porediameter was2.079nm. They both consist of micro pore structure, and pore sizedistribute between1and2nm. They also contain a small amount of middle hole, ofwhich the diameter distributes between3nm and10nm. The biochar and activatedcarbon were characterized under the best conditions of two different methods usingX-ray diffraction, scanning electron microscope(sem), fourier infrared spectrometer,such as measuring their microstructure, surface morphology, surface functionalgroups and so on.We utilize biochar activated carbon under the best conditions of KOH methodand commercial activated carbon as adsorbent to treat the phenol in the phenolwastewater, the initial solution PH, the amount of activated carbon used, initialconcentration of solution, oscillatory time, and the influence of temperature on theadsorption capacity of two types of activated carbon.It has been shown by studies that the zinc chloride method and KOH methodto produce activated carbon from biochar are feasible. They will not only realizethe resourceful use of the biochar, but also add a new understanding for thepreparation of activated carbon and provide actual value for the production ofbiochar activated carbon in the future.