荞麦壳基活性炭的制备及其性能研究

为了实现固废资源化利用,以废弃荞麦壳为原料采用化学活化法制备了一种新型吸附 剂———荞麦壳基活性炭。 采用单因素方法对制备过程中的活化温度、活化时间、活化剂种类和荞 麦壳与活化剂的质量比进行了优化,通过碘值和亚甲蓝值考察了优化后荞麦壳基活性炭的吸附 效能,并采用气体吸附仪、X射线衍射法和扫描电镜分析表征了活性炭的孔结构、微晶结构及微 观表面形貌。 结果表明:当采用磷酸活化剂、活化时间90min、活化温度500℃、荞麦壳与活化剂 的质量比为1∶3时,获得的荞麦壳基活性炭碘值和亚甲蓝值分别为765.8mg/g和222.2mg/g, 其亚甲蓝值高于市售的三种活性炭(煤基、木质、椰壳活性炭);同时,优化后的荞麦壳基活性炭 的中孔孔隙率最大为96.8% ,总孔容量(0.666cm3/g)高于煤基活性炭和椰壳活性炭,比表面积 (785.3m2/g)与市售活性炭相当,说明以荞麦壳为原料采用磷酸活化可制备出中孔发达、吸附性 能好的活性炭。

Preparation and properties of buckwheat shell-based activated carbon

Inordertorealizetheutilizationofsolidwasteresource.Anoveladsorbent,buckwheatshellbasedactivatedcarbonhasbeendevelopedbychemicalactivationwhenapplyingwastebuckwheathull asthrawmaterial.Theauthorsoptimizedtheactivationtemperature,activationtime,typeofactivator, massratioofbuckwheathullandactivatorinthepreparationprocessthroughsinglefactormethod.The adsorptionefficiencyoftheoptimizedbuckwheat-shellactivatedcarbonwasinvestigatedbyiodinevalue andmethylenebluevalue.Porestructure,microcrystallinestructureandmicro-surfacemorphologyofactivatedcarbonwerecharacterizedbygasadsorptioninstrument,X-raydiffractionandscanningelectron microscopy.Theresultsshowedthattheoptimizedbuckwheatshell-basedactivatedcarbonexhibitedthe highestadsorption capacity when applying phosphoric acid as the activator,the activation time of 90min,activationtemperatureof500℃,massratioofbuckwheatshellandactivatoris1∶3.Theiodinevalue and methylene blue value of the optimized buckwheat shell-based activated carbon were 765.8mg/gand222.2mg/grespectively,andthemethylenebluevalueoftheoptimizedbuckwheatshell-basedactivatedcarbonwashigherthanthatofthethreecommercialactivatedcarbons.Moreover, the optimized buckwheat shell-based activated carbon hosted the highest mesopore percentage (96.8%)andhighertotalporevolume(0.666cm3/ g)thanthatofthecoal-basedandcoconutshell activatedcarbons,andtheBETsurfacearea(785.3m2/ g)wassimilartothecommercialactivatedcarbons,indicatingthatanovelbuckwheatshell-basedactivatedcarbonwithstrongmesopore,highadsorptioncapacityhasbeendevelopedwhenapplyingwastebuckwheathullasrawmaterialandphosphateas theactivator.