Photocatalytic Degradation of Textile dye Orange-122 Via Electrospray Mass Spectrometry

Abstract

This work reports the study of the potential application of Zn/TiO2 catalysts, obtained by the solgel method, in processes of environmental decontamination through the reactions of photodegradation of textile dye, followed by electrospray mass spectrometry. The catalysts synthesis was performed according to a 2² factorial design with repetition at the central point. The characterization techniques used were: N2 adsorption measurements (BET method), scanning electron microscopy with energy dispersive X-ray (MEV/EDS), X-ray diffraction and point of zero charge (PZC). The photocatalytic tests were performed in batch in the presence of sunlight, and to evaluate the degradation kinetics study, a rapid direct injection electrospray mass spectrometry (DI-ESI-MS) method has been developed. By the photocatalytic tests, the calcination temperature of 400 °C has shown the best results of discoloration for the reactive Orange-122 dye (99.76%) in a reaction time of 2h. The discoloration kinetics were a pseudo-first order, and a statistical analysis was performed to investigate the effects of the variables and to optimize the conditions of discoloration to the dye. After the reactional time of 2 h, an ion of m/z 441.5 was detected by ESI-MS, indicating that the photocatalytic process was effective for the degradation of the dye to secondary compounds.

Development of Adsorbent Materials Using Residue from Coffee Industry and Application in Food dye Adsorption Processes

“…the process and finally they produce materials with a high content of mesoporous and a high surface area, which can be used for the adsorption of high molecular weight species, such as azo-dyes [22,[24][25][26][27].…”

Production of nanostructured crystalline composite using residual ashes from flocculated sludge burning process in a poultry slaughterhouse wastewater treatment system

“…This showed that adsorbents had a high micropore structure. Besides, no hysteresis loop was observed in the adsorption-desorption of the adsorbents; this indicated that mesopores of adsorbents were at a quite low number or none [26]. Pore size distributions (PSDs) for adsorbents were calculated with the Barret-Joyner-Hallenda (BJH) method [49], using N 2 adsorption branches with results illustrated in Fig.…”

“…In the A.C. (IV) diffractogram, for example, no phase other than quartz was detected, indicating that the unit cell of the crystal lattice of this material was composed basically of the elements silicon and oxygen in a hexagonal arrangement. This change most likely came from the chemical activation with phosphoric acid and heat treatment that this material was subjected to; in fact, the intention of activating an adsorbent is to change its structure to provide the formation of a porous surface with high adsorbent capacity; the fact that the base material was rich in silicon allowed all materials to show peaks related to the silicon oxide phases, a material that is highly known in the literature for being a material with a rich porous structure and high adsorptive capacity [26,44,63].…”

“…Furthermore, most reagents are non-toxic, and activation takes place in a short reaction time and at a low temperature of 300-400 ºC, optimizing this process while lowering energy and personnel expenses. Furthermore, the reagents required are frequently inexpensive, reducing the overall cost of the operation [13,19,[24][25][26], and promoting a more quick and more effective way of treating these effluents, contrary to the conventional methods [26].…”

Estudo da aplicação de bagaço de malte como adsorvente para remoção de óleo lubrificante em meio aquoso / Study of the application of brewers’ spent grains as an adsorbent for the removal of lubricating oil in an aqueous medium

“…Os efluentes aquosos contendo óleos acarretam problemas ambientais quando entram, sem tratamento, em contato com corpos hídricos, como por exemplo a formação de filmes na superfície da água, o que acarreta em um aumento da DQO e DBO daquele ambiente, pela diminuição das trocas gasosas entre o corpo d'agua e a atmosfera uma vez que a incidência de luz é diminuída, o que acarreta na eutrofização daquele corpo d'agua e consequentemente no desbalanceamento entre a fauna e a flora (Magalhães et al, 2013;Hoss et al, 2018). A partir disso, o tratamento correto de efluentes contaminados com óleos lubrificantes é necessário para garantir o cuidado com o meio ambiente, para isso são usualmente utilizados processos de adsorção/absorção com materiais adsorventes e filtrantes para a retirada desses compostos do meio aquoso, porém o elevado custo desses processos gera uma dificuldade em sua aplicação (Castro et al, 2019;Castro et al, 2020;Hoss et al, 2018).…”