Optimization of the decolorization conditions of Rose Bengal by using Aspergillus niger TF05 and a decolorization mechanism

Abstract

Aspergillus niger TF05 was applied to decolorize Rose Bengal dye. The effects of carbon source, nitrogen source, metal ion and spore concentration on Rose Bengal treatment with A. niger TF05 were studied. A Plackett–Burman design (PBD) and a uniform design (UD) were used to optimize the decolorization conditions of A. niger TF05 and enhance its decolorization effect. The mechanism of Rose Bengal decolorization by A. niger TF05 was examined by analysing degradation products via UV–visible light spectroscopy, IR spectroscopy and GC-MS. The best decolorization effect was achieved in the single factor test with glucose and ammonium chloride as carbon and nitrogen sources, respectively. Mg2+ was an essential ion that could improve the mould ball state and adsorption efficiency if the spore concentration was maintained at 106 spores ml–1. The optimal decolorization conditions obtained using the PBD and UD methods were 11.5 g l−1 glucose, 6.5 g l−1 ammonium chloride, 0.4 g l−1 magnesium sulphate, pH 5.8, 28 °C, 140 r.p.m. rotational speed, 0.18 g l−1 dye concentration, 0.5 ml of inocula and 120 h decolorization time. Under these conditions, the maximum decolorization rate was 106%. Spectral analysis suggested that the absorption peak of the product changed clearly after decolorization; GC-MS analysis revealed that the intermediate product tetrachlorophthalic anhydride formed after decolorization. The combined use of the PBD and UD methods can optimize multi-factor experiments. A. niger TF05 decolorized Rose Bengal during intracellular enzymatic degradation after adsorption.

Graphene Loaded ZrO2 Nanocomposite for Antioxidant, Dye Removal, Electrochemical and Green Sensor Studies

“…These composite materials showcase graphene, a sought-after component valued for its significant specific surface area and extensive twodimensional π-π* conjugation structure, contributing to improved electron conductivity. [8][9] In their research, Anjaneyulu and colleagues utilized an in situ-hydrothermal method to synthesize a nanocomposite consisting of ZrO 2 /Fe 2 O 3 /rGO. They evaluated the photo-catalytic activity of these synthesized catalysts under visible source exposure and observed impressive degradation rates of 98.43 % for Congo Red (CR) and 97.76 % for Acetophenone (AP).…”

“…Lately, there has been considerable interest in carbon‐based nanocomposites (NCs) due to their exceptional potential for photocatalysis. These composite materials showcase graphene, a sought‐after component valued for its significant specific surface area and extensive two‐dimensional π‐π* conjugation structure, contributing to improved electron conductivity [8–9] . In their research, Anjaneyulu and colleagues utilized an in situ‐hydrothermal method to synthesize a nanocomposite consisting of ZrO 2 /Fe 2 O 3 /rGO.…”