Facile preparation of lotus seedpod-derived magnetic porous carbon for catalytic oxidation of Ponceau 4R

In this research, magnetic porous carbon was directly synthesized through one-step pyrolysis of FeCl3 – lotus seedpod mixture. Properties of the obtained material were analysed by X-ray powder diffraction, SEM image, nitrogen adsorption isotherm and vibrating sample magnetometer. The results showed that magnetic Fe3O4 particles were successfully formed over material template in 1 hour. The magnetic porous carbon possessed the specific magnetization of 7.13 emu/g, high specific surface area of 288 m2/g and total pore volume of 0.18 cm3/g. The material was subsequently applied as a potential catalyst for Ponceau 4R degradation by H2O2. Parameters including pH, H2O2 concentration, and different types of catalysts were investigated. At pH 3, 200 ppm H2O2, and 0.40 g/L magnetic porous carbon, 83% Ponceau 4R 50 ppm was removed after 120 minutes treatment. Moreover, the catalyst powders were separated from the treated mixture easily by a magnet. Summarily, magnetic porous carbon can promise to be an efficient catalyst in decomposition of Ponceau 4R.

Sawmill waste derived carbon dots as a fluorescent probe for synthetic dyes in soft drinks

Herein, for the first time the carbon dots (CDs) were synthesized by reflux method from sawmill waste material. We also represent a novel strategy based on fluorescent CDs for determination of ponceau 4R and allura red dyes in soft drinks. Interestingly, both the dyes were sensitive and showed effective fluorescence quenching of the CDs owing to the interaction between them. The analytical applicability of CDs were evaluated for detection of both the dyes with a good linear relationship between the concentration range of 0.0 to 3.0 µg mL−1 and having detection limit 0.45 and 0.47 µg mL−1 for allura red and ponceau 4R dyes respectively. Meanwhile, the potential application of this novel fluorescent probe for dyes determination in real samples was validated in different soft drink samples with good accuracy and precision. Thus, these findings provides new insights for the potential risk assessment of both the dyes. Moreover, CDs acted as an excellent fluorescent material in cellular imaging owing to their cellular uptake and localization.

PROCESSOS OXIDATIVOS AVANÇADOS EFICIENTES NA DEGRADAÇÃO DE CORANTES ALIMENTÍCIOS

Neste estudo, os processos oxidativos avançados (POAs) Fenton e Foto-Fenton, foram estudados na degradação dos corantes alimentícios azul Brilhante FCF, vermelho Ponceau 4R e amarelo tartrazina. A presença de corantes alimentícios em efluentes geram problemas ambientais devido à alta coloração e estabilidade dessas moléculas orgânicas, as quais são de difícil degradação e podem gerar subprodutos com alta toxicidade. Os Processos de Fenton e Foto-Fenton apresentam eficiência na degradação de corantes, combinado as vantagens de simplicidade e baixo custo do processo. Foram estudados os POAs, Fenton [combinando o uso de Ferro/peróxido de hidrogênio (H2O2, 36 % v/v) ] e Foto-Fenton [Ferro/peróxido de hidrogênio (H2O2, 36 % v/v) /luz ultravioleta (UV) ]. Os parâmetros de tempo reacional, concentração e tempo de exposição a luz UV, foram avaliados para os corantes descritos com ambos POAs. Os resultados obtidos exibiram grande efetividade para os POAs Fenton e Foto-Fenton na degradação dos corantes azul Brilhante FCF, vermelho Ponceau 4R e amarelo tartrazina. O processo Fenton (Fe/H2O2) apresentou degradação mais efetiva em menor tempo reacional para os corantes estudados. Assim, podemos destacar que os POAs estudados Fenton e Foto-Fenton, destacam-se como uma importante metodologia para tratar efluentes industriais contendo corantes alimentícios, combinando as vantagens de facilidade, efetividade e baixo custo no processo.

Catalytic Oxidation of Ponceau 4R in Aqueous Solution using Iron-impregnated Al-pillared Bentonite: Optimization of the Process

The application of the Fenton-like process for the oxidation of an aqueous solution of Ponceau 4R dye, using an aluminum pillared clay impregnated with iron (Fe(wt%)/Al-PILC) as catalyst, was investigated. The Response Surface Methodology (RSM), based on a Central Composite Design (CCD) was used to evaluate and optimize the oxidation process of a Ponceau 4R solution. Three independent variables were studied in the experimental design: the amount of H2O2 expressed in multiples of times of stoichiometry dose, iron concentration incorporated by impregnation onto aluminum pillared clay (Fe(wt%)), and amount of catalyst (Fe(wt%)/Al-PILC). The response variables were decolorization and total organic carbon (TOC) removal. The significance of independent variables and their interactions were tested by means of analysis of variance (ANOVA), with a 95% confidence level. With low stoichiometric dose of H2O2 (0.96 and 1.54 times), medium amount of catalyst (374.4 and 391.3 mg) and high Fe concentration impregnated in pillared clay (9.3 and 7.7 wt%), the total decolorization and high TOC removal were achieved. Under multi-objective optimization conditions (3.0 times the stoichiometric dose of H2O2, 420 mg Fe(wt%)/Al-PILC and 5.5 wt% Fe impregnated in Al-PILC), it was possible to achieve 86.18% decolorization and 66.81% TOC removal after 5 h of reaction at 25 °C, with the additional advantage of showing an iron leaching of less than 0.10 mg/L. The established models' soundness is confirmed by a good fit between predictive models and experimental results. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).