Microcystis aeruginosa Synergistically Facilitate the Photocatalytic Degradation of Tetracycline Hydrochloride and Cr(VI) on PAN/TiO2/Ag Nanofiber Mats

Abstract

Cyanobacterial blooms can cause serious damage to aquatic ecosystems. However, we have demonstrated that typical algae-blooming species Microcystis aeruginosa (M. aeruginosa) combined with photocatalysts could synergistically facilitate the photodecontamination of tetracycline hydrochloride (TC) and Cr(VI). In this study, for the first time, harmful algae were successfully converted into photoreactive bionano hybrid materials by immobilizing M. aeruginosa cells onto polyacrylonitrile (PAN)-TiO2/Ag hybrid nanofibers, and their photocatalytic activity was evaluated. The addition of M. aeruginosa significantly improved the photodecontamination, and the reaction rate constant (k) values of TC and Cr(VI) degradation by M. aeruginosa-PAN/TiO2/Ag nanofiber mats were 2.4 and 1.5-fold higher than that of bare PAN/TiO2/Ag nanofiber. Photoreaction caused damage to algae cells, but no microcystin was found that had been photodegraded simultaneously. The effects of various active species were also investigated, and the photodegradation mechanism was proposed. Recycling tests revealed that this flexible M. aeruginosa-PAN/TiO2/Ag hybrid mat had potential application in the removal of mixed organic and inorganic pollutants with high efficiency and without secondary pollutants. Thus, harmful algae blooms could serve as an efficient materials to remove toxic pollutants in a sustainable way under visible light irradiation.

Revisiting the mechanistic pathways for bacterial mediated synthesis of noble metal nanoparticles

“…Extracellular reduction of palladium to PdNPs by Geobacter sulfurreducens was reported as a sustainable method to recover precious metal catalysts (Yates et al, 2013). Another recent investigation pointed out the selective electrocatalysis of biofuel molecular oxidation using palladium nanoparticles generated on Shewanella oneidensis MR-1 (Wu et al, 2018).…”

“…Whereas, these mechanisms may also assist in elucidating the antibiotic resistance phenomena (Engel, 2017, Waseem et al, 2019. The worldwide upsurge in antibiotic resistance has become a severe concern for modern medicine (Goossens et al, 2005, Neu, 1992, Yelin and Kishony, 2018.…”

Simultaneous remediation of hexavalent chromium and organic pollutants in wastewater using period 4 transition metal oxide-based photocatalysts: a review

“…The M. aeruginosa-assisted silver doped on titanium dioxide-supported polyacrylonitrile nanofiber (PAN/TiO 2 /Ag) photocatalyst was used in this study. Impressively, the composite M. The changing color of graphitic carbon nitride was due to the excessive trivalent chromium that adsorbs onto the surface catalyst surface (Wang et al 2020) aeruginosa-assisted PAN/TiO 2 /Ag has astonishing performance in reducing hexavalent chromium and degrading tetracycline hydrochloride under visible light exposure (Wang et al 2018). About 96% of tetracycline hydrochloride and 75% of hexavalent chromium are removed within 240 min of reaction time at pH 6 in mixed pollutant system.…”

“…In this study, M. aeruginosa helps the photocatalytic system by releasing numerous kinds of intracellular substances into the aqueous solution when exposed to the light source (Zhang and Ma 2013;Wang et al 2017). The release of intracellular substances such as organic acids and chlorophylls is capable of capturing the free holes and cause the successful separation of photoproduced electron-holes pairs, which subsequently facilitate the reduction of hexavalent chromium ions (Wang et al 2018).…”

Dye-sensitized Photocatalyst of Sepiolite for Organic Dye Degradation

“…In order to elucidate the role of responsible reactive species for RhB degradation, several scavenger reagents were tested, as shown in Figure 8, where isopropyl alcohol (IPA), benzoquinone (BQ), and potassium iodide (KI) were used as the scavenger reagents for h + , • O 2 − , and • OH, respectively [54][55][56][57].…”