Study Of Bismuth Oxychloride Photocatalytic Removal Of Atenolol In Water

Atenolol is a heart selective beta-blocker,and a kind of pharmaceuticals and personal care products.As a cardiovascular drug,atenolol has been used for more than 30 years.In general,atenolol exposure is not easy to cause acute toxicity,but it is potentially toxic and accumulative in biology because of its long-time existing in environment.Due to atenolol cannot be completely removed by traditional wastewater treatment,the concentration of atenolol is relatively high in environment.Therefore,it is essential to develop new techniques to remove atenolol in water.Research theories and results on removing atenolol are helpful for developing removal techniques and the understandings of the migrations of pollutants.Our study focuses on the photocatalytic degradation and the removal of atenolol from water by bismuth oxychloride(BiOCl).Firstly,reaction kinetics and mechanisms were systematically investigated based on identification of reaction products by liquid chromatograpy-mass spectrometry(LC-MS).Secondly,the influences of natural organic matter and graphene on the catalytic reaction were investigated.Finally,we tried to prepare hydrogel of BiOCl and apply it to the water purifier to achieve the goal of removing atenolol.The specific conclusions are as follows:(1)BiOCll-photocatalytic removal of atenolol.Characterization results show that the synthesised BiOCl photocatalyst are rectangle and irregularly pieces of nanoparticles.The removal of atenolol is related to the concentration of BiOCl,and with the increase of BiOCl the removal rate increased.These reactions follow zero order reaction kinetics;The stability and recyclability of BiOCll photocatalyst are very good and after 10 cycles,the removal of atenolol still reached 90%The natural organic matter and graphene inhibited the degradation of atenolol.Characteristics of indirect band gap,internal electric field and layered structure of BiOCl,are conducive to its excellent photocatalytic performance.(2)Products characterization and reaction pathway.According to the identified reaction products,three pathways were proposed.Firstly,the radical H2NCO-of atenolol was exposed to hydroxyl and fall off from the matrix,then it can be oxidized by molecular oxygen to be product 1(m/z 237).After further oxidation,the product 1 converted to product 2(m/z 253)after single hydroxylation on the benzene ring.Secondly,atenolol converted into product 4(m/z 298)after double hydroxylation on the benzene ring.Finally,atenolol became product 3(m/z 280)after single hydroxylation on the benzene ring and oxidative dehydrogenation into carbonyl on the carbon chain.(3)The catalytic reaction mechanism and the deactivation reason.The photogenerated electrons(e-)and holes(h+)were produced when the BiOCl was illuminated by sunlight.The corresponding photogenerated holes(h+)would quickly transfer to the valence band(VB)occupied by Bi 6p from the valence band(VB)occupied by Bi 6pCl 3P and O 2P of BiOCll.Then O2 molecules would react with e-to generate ·O2-active radicals during this process.Furthermore,the corresponding photogenerated holes(h+)would react with H2O and OH-to generate ·OH.This active radicals could remove contaminants by oxidation-reduction reactions.The deactivation of BiOCl during removing atenolol in aqueous medium,resulting in reduced degradation rate of atenolol was observed.It is inferred from the studies by various characterization techniques that it may be due to surface adsorption of some products reducing the number of available surface active sites.(4)The practical applications of BiOCl.We prepared hydrogel of BiOCl using graphene oxide and ruthenium compound,but the results of immobilization and the removal of atenolol are not ideal.We need to strengthen it in terms of transparency,conductivity and mechanical properties.Also we design a water filter to remove atenolol,and the most precious is that we use water flow to drive turbine blades to mix water with little energy and cost.In addition,the equipment is suitable for different pollution degree of wastewater treatment own to the intermittent or continuous operation flexibly.