Preparation And Photocatalytic Properties Of Porous Carbon Composites From Biomass

The porous carbon composite photocatalytic materials have the advantages of large specific surface area,large light absorption range and suitable energy band gap in the UV region,which is conducive to the degradation of organic dye pollutants in sewage and improve the efficiency of photodegradation of dye.The photodegradation experiment of porous carbon composite from Tamarix Ramosissima was conducted to provide technical support for the treatment of environmental pollution caused by dye wastewater.The porous carbon materials（TL700,TL800,TL900）of Tamarix Ramosissima were obtained from Tamarix Ramosissima by activating it with KOH solution and hydrochloric acid solution in turn.The morphology,structure and properties of the porous carbon materials were characterized by field emission scanning electron microscopy（SEM）,Fourier transform infrared spectroscopy（FT-IR）,Raman spectroscopy（Raman）,N₂ adsorption-desorption curve（BET）,cyclic voltammetry（CV）and AC impedance method（EIS）.The results show that the porous carbon materials of Tamarix Ramosissima have abundant pore channels and active sites,as well as surface active functional groups such as-OH,CO,-COOH and C-O-C,which have certain conductivity and electron storage capacity.The porous carbon/Ag₃PO₄ composite photocatalyst was prepared from Tamarix Ramosissima Ramosissima with Ag NO₃ solution and Na₃PO₄ solution at different concentrations in one step.It was found that the composite was successfully supported with Ag₃PO₄ photocatalyst,and the best degradation performance was obtained when the pyrolysis temperature of porous carbon was 800℃,the concentration of Ag NO₃ solution was 0.2 mol/L,the concentration of Na₃PO₄ solution was 0.15 mol/L and the p H of dye solution was 7.The photodegradation rate of Rhodamine B solution of 20 mg/L was tested for 90 min after 45 min of adsorption under UV-VIS illumination.The porous carbon/Ag₃PO₄/nano-TiO₂ composite was prepared from Tamarix Ramosissima,Ag NO₃ and Na₃PO₄ solutions of different concentrations and nano-Ti O₂ in two steps.Porous carbon/Ag₃PO₄/nano-Zn O composites were prepared from Tamarix Ramosissima Tamarix,Ag NO₃ and Na₃PO₄ solutions,Zn NO₃·6H₂O and KOH solutions at different concentrations in a two-step process.The results show that photocatalyst particles and photocatalytic active substances are successfully loaded on the surface and pore of the composite.The irregular pores formed by it expose more active sites,which is conducive to the process of photocatalytic reaction.Porous carbon of Tamarix Ramosissima can be used as electron acceptor,which weakens the recombination of photoelectrons and holes and further enhances the photocatalytic activity.The results of photodegradation test showed that the green photodegradation rate of malachite by porous carbon/Ag₃PO₄/nano-Ti O₂ composite was up to95%in the degradation experiment of 20 mg/L dye solution,which was 12%higher than that before Ti O₂ was loaded.The photodegradation rate of porous carbon/Ag₃PO₄/nano-Zn O composite is up to 92%in the degradation experiment of 20 mg/L dye solution,which is 11%higher than that before loading nano-Zn O.