Photocatalytic Oxidation of Diuron over biomass based CQDs/TiO2 catalysts

Project no. 32681 · Status: Kapanmış · 2024

Summary

<p>In&nbsp;agricultural&nbsp;practices,&nbsp;herbicides&nbsp;such&nbsp;as&nbsp;Diuron&nbsp;(DRN)&nbsp;are&nbsp;commonly&nbsp;used&nbsp;to&nbsp;increase&nbsp;crop&nbsp;yield&nbsp;and&nbsp;control&nbsp;undesired&nbsp;weeds&nbsp;that&nbsp;may&nbsp;damage&nbsp;crops.&nbsp;However,&nbsp;excessive&nbsp;use&nbsp;of&nbsp;these&nbsp;herbicides&nbsp;leads&nbsp;to&nbsp;their&nbsp;penetration&nbsp;into&nbsp;the&nbsp;soil,&nbsp;causing&nbsp;toxic&nbsp;effects&nbsp;on&nbsp;plants,&nbsp;and&nbsp;when&nbsp;released&nbsp;into&nbsp;clean&nbsp;water&nbsp;resources,&nbsp;they&nbsp;contribute&nbsp;to&nbsp;environmental&nbsp;pollution.&nbsp;Diuron,&nbsp;with&nbsp;a&nbsp;half-life&nbsp;of&nbsp;approximately&nbsp;300&nbsp;days,&nbsp;poses&nbsp;a&nbsp;serious&nbsp;threat&nbsp;due&nbsp;to&nbsp;its&nbsp;carcinogenic&nbsp;and&nbsp;genotoxic&nbsp;properties.&nbsp;Therefore,&nbsp;it&nbsp;is&nbsp;crucial&nbsp;to&nbsp;treat&nbsp;this&nbsp;pollutant&nbsp;prior&nbsp;to&nbsp;its&nbsp;discharge&nbsp;into&nbsp;the&nbsp;environment&nbsp;in&nbsp;order&nbsp;to&nbsp;protect&nbsp;ecosystems&nbsp;and&nbsp;ensure&nbsp;sustainability.&nbsp;Various&nbsp;methods,&nbsp;including&nbsp;filtration,&nbsp;adsorption,&nbsp;and&nbsp;advanced&nbsp;oxidation&nbsp;processes,&nbsp;have&nbsp;been&nbsp;employed&nbsp;for&nbsp;this&nbsp;purpose.&nbsp;Among&nbsp;these&nbsp;methods,&nbsp;advanced&nbsp;oxidation&nbsp;processes&nbsp;stand&nbsp;out&nbsp;due&nbsp;to&nbsp;their&nbsp;low&nbsp;cost&nbsp;and&nbsp;high&nbsp;efficiency.&nbsp;Considering&nbsp;reaction&nbsp;efficiency,&nbsp;the&nbsp;selection&nbsp;of&nbsp;the&nbsp;catalyst&nbsp;plays&nbsp;a&nbsp;critical&nbsp;role.&nbsp;In&nbsp;this&nbsp;project,&nbsp;the&nbsp;photocatalytic&nbsp;oxidation&nbsp;of&nbsp;DRN&nbsp;was&nbsp;investigated&nbsp;over&nbsp;Ag-loaded&nbsp;CQD/TiO<sub>2</sub>&nbsp;composites.&nbsp;The&nbsp;carbon&nbsp;quantum&nbsp;dots&nbsp;(CQDs)&nbsp;employed&nbsp;in&nbsp;the&nbsp;photocatalytic&nbsp;oxidation&nbsp;of&nbsp;DRN&nbsp;was&nbsp;synthesized&nbsp;from&nbsp;lemon&nbsp;peels&nbsp;via&nbsp;a&nbsp;microwave-assisted&nbsp;method.&nbsp;The&nbsp;prepared&nbsp;CQDs,&nbsp;CQD/TiO<sub>2</sub>&nbsp;and&nbsp;Ag-loaded&nbsp;CQD/TiO<sub>2</sub>&nbsp;photocatalysts&nbsp;were&nbsp;characterized&nbsp;using&nbsp;Fourier&nbsp;Transform&nbsp;Infrared&nbsp;(FTIR)&nbsp;Spectroscopy,&nbsp;X-ray&nbsp;Photoelectron&nbsp;Spectroscopy&nbsp;(XPS),&nbsp;Ultraviolet-Visible&nbsp;(UV-Vis)&nbsp;Spectroscopy,&nbsp;X-ray&nbsp;Diffraction&nbsp;(XRD),&nbsp;Transmission&nbsp;Electron&nbsp;Microscopy&nbsp;(TEM&nbsp;and&nbsp;SEM),&nbsp;and&nbsp;Photoluminescence&nbsp;(PL)&nbsp;analysis.&nbsp;In&nbsp;addition,&nbsp;the&nbsp;photoelectrochemical&nbsp;properties&nbsp;of&nbsp;the&nbsp;composites,&nbsp;including&nbsp;photocurrent&nbsp;response&nbsp;and&nbsp;electrochemical&nbsp;impedance&nbsp;(IMPS/IMVS),&nbsp;were&nbsp;analyzed&nbsp;using&nbsp;a&nbsp;potentiostat/galvanostat.&nbsp;At&nbsp;the&nbsp;end&nbsp;of&nbsp;the&nbsp;300-minute&nbsp;reaction&nbsp;time,&nbsp;the&nbsp;degradation&nbsp;efficiencies&nbsp;for&nbsp;TiO<sub>2</sub>,&nbsp;LPCQD/TiO<sub>2</sub>,&nbsp;and&nbsp;Ag@LPCQD/TiO<sub>2</sub>&nbsp;were&nbsp;found&nbsp;to&nbsp;be&nbsp;3.5%,&nbsp;17.1%,&nbsp;and&nbsp;68.9%,&nbsp;respectively.&nbsp;Integrating&nbsp;LPCQD&nbsp;into&nbsp;the&nbsp;TiO₂&nbsp;structure&nbsp;provided&nbsp;an&nbsp;improvement&nbsp;in&nbsp;photocatalytic&nbsp;activity.&nbsp;The&nbsp;addition&nbsp;of&nbsp;Ag&nbsp;nanoparticles&nbsp;to&nbsp;the&nbsp;LPCQD/TiO₂&nbsp;composite&nbsp;significantly&nbsp;increased&nbsp;the&nbsp;photodegradation&nbsp;efficiency.&nbsp;The&nbsp;highest&nbsp;degradation&nbsp;efficiency&nbsp;of&nbsp;97%&nbsp;was&nbsp;observed&nbsp;at&nbsp;a&nbsp;pH&nbsp;of&nbsp;3,&nbsp;an&nbsp;initial&nbsp;DRN&nbsp;concentration&nbsp;of&nbsp;2.5&nbsp;ppm,&nbsp;and&nbsp;a&nbsp;catalyst&nbsp;amount&nbsp;of&nbsp;1.5&nbsp;g/L.&nbsp;Within&nbsp;the&nbsp;scope&nbsp;of&nbsp;the&nbsp;project,&nbsp;intermediate&nbsp;products&nbsp;formed&nbsp;during&nbsp;photocatalytic&nbsp;oxidation&nbsp;were&nbsp;determined.&nbsp;Photocatalytic&nbsp;oxidation&nbsp;was&nbsp;also&nbsp;carried&nbsp;out&nbsp;using&nbsp;river&nbsp;water,&nbsp;and&nbsp;the&nbsp;effect&nbsp;of&nbsp;anions&nbsp;on&nbsp;oxidation&nbsp;was&nbsp;investigated.</p>

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