Dual role of chemically functionalized activated carbon fibres: investigation of parameters influencing the degradation of organophosphorus compounds and antibacterial behaviour

Abstract

BACKGROUND An efficient material possessing both photocatalytic and antimicrobial properties is necessary to remediate contaminated water resources. In the present study, zinc oxide nanorods (ZnO) have been impregnated on activated carbon fibres (ACF) to develop a heterogeneous photocatalytic system for the degradation of an organophosphorus compound, taking Malathion as a model pollutant, and to investigate the antibacterial efficiency of the former. RESULTS The efficiency of Malathion removal varies with catalyst dosage, initial concentration of Malathion, and also depends on the interference from inorganic ions such as chloride, nitrate, sulfate, phosphate and bicarbonate in the contaminated solution. The role played by the highly active radicals in the degradation process is inevitable, confirmed by the addition of radical scavengers during the reaction. Hydroxyl radicals were found to be the most active species accountable for the degradation of Malathion. Moreover, OH trapping experiments conducted by measuring photoluminescence (PL) intensity concluded that greater amounts of OH radicals are generated with increase in time. Reusability and long‐term stability of the composite was validated for up to five degradation cycles. The developed composite also possesses microbial decontamination capabilities, verified by studying antibacterial assay against Gram positive Staphylococcus aureus and Gram negative strains of Pseudomonas aeruginosa and Klebsiella Pneumoniae. CONCLUSION Dual functional and reusable ZnO rods/ACF composites were developed using a simple, low cost hydrothermal method, and could be used as a potential candidate for water treatment applications. © 2018 Society of Chemical Industry

Photocatalytic Degradation of a Chlorinated Organic Chemical Using Activated Carbon Fiber Coupled with Semiconductor

“…It was observed that bicarbonate ions have beneficial effect on the degradation since the decrease in relative concentration of 2,4-dichlorophenol was higher when compared to the reaction carried out without anions. The results are in contradictory to the previous reports stating that carbonate and bicarbonate ions scavenged the hydroxyl radicals which resulted in the decrease in photocatalytic activity of ZnO (9,27). Phosphate ions were observed to exhibit detrimental effects as the change in concentration of 2, 4-dichlorophenol was followed by sulfate ions.…”

“…However, the addition of PBQ and IPA too quenched the reaction to a certain extent but not as much as KI has quenched. The decrease in removal efficiency was observed to be of following order: No scavenger (96.52%) < PBQ (57.64%) < IPA (54.78%) < KI (49.18%).The results are in contrary to the previous reports since the addition of PBQ and KI did not show much effect in the removal efficiency and IPA was the sole participant in the degradation process (9,30). If hydroxyl radicals were the main active species, then addition of bicarbonate ions (previous section) should have quenched the reaction since bicarbonate ions also scavenge hydroxyl radicals according to the following reaction (27).…”

“…Heterogeneous photocatalytic system based on metal oxides has attracted wide attention. Zinc oxide is the most widely studied photocatalytic material . However, the difficulty incurred in the recovery of powdered metal oxides is limiting its usage.…”

Study of thermomechanical, structural and antibacterial properties of poly(lactic acid) reinforced with graphene oxide nanoparticles via melt mixing

“…Therefore, it is desirable to create antibacterial PLLA composites using GO as an antibacterial agent. Fundamental mechanisms of the bacteriostatic/bactericidal properties of nanomaterials are demonstrated to be physical disruption of cellular systems via direct interaction between nanomaterial and microorganism 7 . A subsequent mechanism is due to the generation of oxidative stress through the elevated reactive oxygen species levels 7 .…”

“…Fundamental mechanisms of the bacteriostatic/bactericidal properties of nanomaterials are demonstrated to be physical disruption of cellular systems via direct interaction between nanomaterial and microorganism 7 . A subsequent mechanism is due to the generation of oxidative stress through the elevated reactive oxygen species levels 7 . These processes result in inhibition of respiratory enzymes, ATP production and disruption of membrane integrity and transport processes in the biological system that ultimately leads to the death of bacterial cells 8 …”