Designing novel MgFe2O4 coupled V2O5 nanorod for synergetic photodegradation of tetracycline with enhanced visible-light energy harvesting: Photoluminescence, kinetics, intrinsic mechanism and bactericidal effect

Tecoma stans floral extract-mediated synthesis of MgFe2O4/ZnO nanoparticles for adsorption and photocatalytic degradation of coomassie brilliant blue dye

Toxic organic dyes-containing wastewater treatment by adsorption and photocatalytic techniques is widely applied, but adsorbents and photocatalysts are often synthesized through chemical methods, leading to secondary pollution by released chemicals. Here, we report a benign method using Tecoma stans floral extract to produce MgFe2O4/ZnO (MGFOZ) nanoparticles for adsorption and photocatalytic degradation of coomassie brilliant blue (CBB) dye. Green MGFOZ owned a surface area of 9.65 m2/g and an average grain size of 54 nm. This bio-based nanomaterial showed higher removal percentage and better recyclability (up to five cycles) than green MgFe2O4 and ZnO nanoparticles. CBB adsorption by MGFOZ was examined by kinetic and isotherm models with better fittings of Bangham and Langmuir or Temkin. RSM-based optimization was conducted to reach an actual adsorption capacity of 147.68 mg/g. Moreover, MGFOZ/visible light system showed a degradation efficiency of 89% CBB dye after 120 min. CBB adsorption can be controlled by both physisorption and chemisorption while •O2- and •OH radicals are responsible for photo-degradation of CBB dye. This study suggested that MGFOZ can be a promising adsorbent and catalyst for removal of organic dyes in water.

Construction of p-n-p nano heterojunction through coupling La2O3, (BiO)2CO3 and Ag3PO4 for effective photocatalytic degradation of doxycycline: Insights into mechanism, pathway and intermediate toxicity evaluation

The present work is centred around the development of La2O3/(BiO)2CO3/Ag3PO4 (LBA), a p-n-p nano-heterojunction to photodegrade doxycycline under visible light irradiation. Here, ultrasonication assisted co-precipitation method was employed to synthesize the photocatalyst. The photocatalyst was characterized using different analysis such as SEM, TEM, elemental mapping, XRD, XPS, FTIR, Raman, BET, DRS, PL and EIS which confirmed the successful fabrication of LBA and their excellent ability to refrain the e-/h+ recombination owing to the construction of the heterojunction. LBA was found to degrade DOX by 91.75 % with the high mineralization of 87.23%. The impact of the reaction parameters influencing the photodegradation process including the concentration of the NCs and DOX, pH and the influence of the commonly present anions were studied. The stability and reusability of the LBA was assessed through subjecting it to four cycles of photodegradation of DOX. In addition, the recovered LBA was characterized through XPS and XRD analysis to confirm the particles stability and reusability. The active participation of the photogenerated charges and the reactive oxygen species were identified through the scavenging assay and ESR analysis. Further, GC-MS/MS analysis was performed to put forward a plausible photodegradation pathway. The toxicity of the end products as well as the intermediates was predicted through ECOSAR software.

Preparation of antibacterial Zn and Ni substituted cobalt ferrite nanoparticles for efficient biofilm eradication

Zinc (Zn) and, alternatively, nickel (Ni) substituted cobalt ferrite (CF) nanoparticles (NPs) were prepared by sol-gel method. X-ray diffraction analysis revealed the formation of cubic structure of cobalt ferrite. FTIR analysis confirmed the vibrational band located at 550-580 cm^-1 that belongs to the M - O bond (M = Ni, and Zn). The alteration of the surface morphology of CF after the addition of Zn and Ni ions was observed from scanning electron microscopic images. The additional peaks in the energy dispersive X-ray diffraction (EDX) analysis spectra were found to correspond to Zn and Ni. The presence of Zn and, alternatively, Ni ions enhanced the biocidal properties of CF NPs against gram negative organisms, in a concentration and time-dependent manner. Furthermore, exposure to CF, CF-Zn and CF-Ni NPs decreased metabolic activity due to the damage of extra polymorphic substances, live/dead cell variation, architecture and surface integrity of the cells. Altogether, the present investigation provides the basis of metal ion substituted metal oxide NPs as anti-biofilm agents against gram-positive and gram-negative bacteria.