Skip to Content
Merck
CN
  • Photocatalytic degradation of carbamazepine in wastewater by using a new class of whey-stabilized nanocrystalline TiO2 and ZnO.

Photocatalytic degradation of carbamazepine in wastewater by using a new class of whey-stabilized nanocrystalline TiO2 and ZnO.

The Science of the total environment (2014-04-15)
D P Mohapatra, S K Brar, R Daghrir, R D Tyagi, P Picard, R Y Surampalli, P Drogui
ABSTRACT

Nanoscale photocatalysts have attracted much attention due to their high surface area to volume ratios. However, due to extremely high reactivity, TiO2 and ZnO nanoparticles prepared using different methods tend to either react with surrounding media or agglomerate, resulting in the formation of much larger flocs and significant loss in reactivity. This work investigates the photocatalytic degradation of carbamazepine (CBZ), a persistent pharmaceutical compound from wastewater (WW) using TiO2 and ZnO nanoparticles prepared in the presence of a water-soluble whey powder as stabilizer. The TiO2 and ZnO nanoparticles prepared in the presence of whey stabilizer displayed much less agglomeration and greater degradation power than those prepared without a stabilizer. Higher photocatalytic degradation of carbamazepine was observed (100%) by using whey stabilized TiO2 nanoparticles with 55 min irradiation time as compared to ZnO nanoparticles (92%). The higher degradation of CBZ in wastewater by using TiO2 nanoparticles as compared to ZnO nanoparticles was due to formation of higher photo-generated holes with high oxidizing power of TiO2. The photocatalytic capacity of ZnO anticipated as similar to that of TiO2 as it has the same band gap energy (3.2 eV) as TiO2. However, in the case of ZnO, photocorrosion frequently occurs with the illumination of UV light and this phenomenon is considered as one of the main reasons for the decrease of ZnO photocatalytic activity in aqueous solutions. Further, the estrogenic activity of photocatalyzed WW sample with CBZ and its by-products was carried out by yeast estrogen screen (YES) assay method. Based upon the YES test results, none of the samples showed estrogenic activity.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Acetone, natural, ≥97%
Supelco
Ethanol solution, certified reference material, 2000 μg/mL in methanol
Supelco
Carbamazepine, Pharmaceutical Secondary Standard; Certified Reference Material
Sigma-Aldrich
Carbamazepine, meets USP testing specifications
Supelco
Ethanol standards 10% (v/v), 10 % (v/v) in H2O, analytical standard
Supelco
Acetone, analytical standard
Supelco
Methanol, analytical standard
Sigma-Aldrich
Ethanol Fixative 80% v/v, suitable for fixing solution (blood films)
Sigma-Aldrich
Methanol, anhydrous, 99.8%
Sigma-Aldrich
Acetone, ≥99%, meets FCC analytical specifications
Sigma-Aldrich
Methanol, purification grade, 99.8%
Supelco
Dehydrated Alcohol, Pharmaceutical Secondary Standard; Certified Reference Material
Sigma-Aldrich
Methanol, suitable for NMR (reference standard)
Sigma-Aldrich
Methanol, suitable for HPLC, gradient grade, ≥99.9%
Sigma-Aldrich
Methanol, BioReagent, ≥99.93%
Sigma-Aldrich
Ethyl alcohol, Pure 190 proof, for molecular biology
Sigma-Aldrich
Acetone, HPLC Plus, for HPLC, GC, and residue analysis, ≥99.9%
Sigma-Aldrich
Methanol, suitable for HPLC, gradient grade, suitable as ACS-grade LC reagent, ≥99.9%
Sigma-Aldrich
Acetone, suitable for HPLC, ≥99.9%
Supelco
Methanol, Pharmaceutical Secondary Standard; Certified Reference Material
Supelco
Carbamazepine, analytical standard
Supelco
Acetone, Pharmaceutical Secondary Standard; Certified Reference Material
Supelco
Acetonitrile(Neat), Pharmaceutical Secondary Standard; Certified Reference Material
USP
Acetone, United States Pharmacopeia (USP) Reference Standard
Carbamazepine, European Pharmacopoeia (EP) Reference Standard
Supelco
Residual Solvent - Acetonitrile(solution in DMSO), Pharmaceutical Secondary Standard; Certified Reference Material
Sigma-Aldrich
Methanol, ACS spectrophotometric grade, ≥99.9%
Sigma-Aldrich
Methanol, ACS reagent, ≥99.8%
Sigma-Aldrich
Methanol, Laboratory Reagent, ≥99.6%
Sigma-Aldrich
Methanol, ACS reagent, ≥99.8%