Adsorption-photocatalytic Degration Of Naphthalene By Coal-based Activated Carbon Loaded TiO₂

Polycyclic aromatic hydrocarbons?PAHs?pollutants have been identified as carcinogenic,mutagenic and teratogenic with persistance,bioaccumulation,high toxicity and hard degradation.Thus,it had caused serious pollution to environment and human health.It has attracted people's widespread attention for choosing appropriate approach and method for removal of PAHs.Photocatalytic technology has been an alternative technology because of its cheapness and nontoxicity.And,TiO₂ photocatalysts have attracted a lot of attention due to its cheapness and nontoxicity,good chemical stability and relatively high photocatalytic activity.However,TiO₂ has low surface,wide band gap,high recombantion rate of photogenerated electrons-holes and low photocatalytic efficiency.While preparation method requires long heating time lead large amount wasted of energy.Thus,in order to solve these problems,in this paper,coal-based activated carbons?CAC?and titanium dioxide nanoparticles loaded onto activated carbon?TiO₂/AC?are preared by microwave-assisted.The TiO₂/AC was modified by metallic element with La,Ce and Ag,non-metallic element with N?P and ?-CD for adsorption-photocatalytic degration of naphthalene.The results as following:The adsorption capacity of the obtained activated carbons?prepared under the optimum power level?towards naphthalene follows the order: ACAC > BCAC > LCAC.In addition,the textural properties of the CACs were investigated by means of SEM and low-temperature N2 adsorption.The surface chemistry features of the CACs were investigated by XPS,FTIR spectroscopy and Boehm's titration method.ACAC has a higher surface area,pore volume,and zero point charge?pHPZC?than the BCAC and LCAC,while acidic oxygen functional group of the ACAC is lower than that of BCAC and LCAC.In addition,the adsorption of naphthalene from the aqueous solution on the CACs could be favorably described by the Freundlich isotherm.The adsorption kinetics fits very well to the pseudo-second-order model.Among the three coals,A-coal was the best material having low ash content and less than 10% volatile content,which is beneficial for the preparation of CAC using microwave-assisted synthesis for naphthalene adsorption.La and N co-doped TiO₂/AC can promote the separation of the photogenerated electrons and holes.N doping into TiO₂ which forming a new orbit hybridization between the conduction band of Ti 3d and the valence band of O 2p,and La3+ doped into TiO₂/AC appeared a new band below the conduction band,which narrowed the band gap of TiO₂ from 3.01 to 2.67 eV.The 0.001La-N-TiO₂/AC photocatalyst exhibited the highest degradation efficiency of 93.5% for naphthalene under visible light within 120 min.the photocatalytic activity of the recovered La-N-TiO₂/AC photocatalyst still reached 92.2% after five recycling runs.This result indicated that 0.001La-N-TiO₂/AC photocatalyst is highly effective and stable.This study focused on the microwave-assisted one-step synthesis and evaluation of visible light-sensitized Ce,N,and P tri-doped titanium dioxide nanoparticles loaded on activated carbon?TiO₂/AC?photocatalyst for the photocatalytic degradation of naphthalene.The main research is to study Ce,N,and P doping on TiO₂/AC to degrade naphthalene.Results show that the optimal doping amount of Ce and P is 0.3 g and 5%,respectively,and the photocatalytic degradation rate of naphthalene were 77.4% and 75.5%,respectively.While Ce,N,and P tr-doped TiO₂/AC increased the photocatalytic degradation rate and redued the band gap.The photocatalytic degradation rate of naphthalene was 97.9%.The apparent rate constant of Ce-N-P-TiO₂/AC photocatalyst was 5.0 times than that of TiO₂/AC.The photocatalytic activity of the recovered Ce-N-P-TiO₂/AC photocatalyst showed no noticeable change and still reached 97.0% after five recycling runs,indicating that Ce-N-P-TiO₂/AC photocatalyst is highly effective and stable under visible light irradiation.This study describes the microwave-assisted one-step synthesis of Ag and ?-cyclodextrin??-CD?co-doped TiO₂/AC with dominating {001} facets,using NaF as a morphology controlling agent,for photocatalytic degradation of naphthalene.F doping inhibited the anatase-to-rutile phase transformation.?-CD effectively played a "bridge" role,using the efficient transmission electron of ?-CD and synergistic effects between Ag and ?-CD,improving TiO₂/AC photocatalyst for photocatalytic degradation of naphthalene.Hydroxyl radicals?×OH?play an important role in naphthalene photodegradation.F-Ag-?-CD/TiO₂/AC with exposed {001} facets exhibited the highest photocatalytic activity?98.4%?and rate constant under visible-light irradiation?150 min?.In addition,the photocatalyst also displayed excellent photocatalytic stability.