Hybrid sol–gel silica adsorbent material based on grape stalk applied to cationic dye removal

Abstract

The removal of azo‐dyes, recalcitrant compounds found in several industrial effluents, was investigated by an environmentally friendly hybrid adsorbent material based on grape stalk encapsulated by the sol–gel method. The winemaking process produces a large amount of grape stalk. This solid waste represents an environmental problem for wineries. The hybrid adsorbent based on grape stalk was synthetized by the acid catalyzed sol–gel route and characterized by different techniques. According to the zeta potential values, the resulting hybrid material is negatively charged at a wide pH range (2.0–12.0). The adsorption of the cationic azo‐dye Basic Blue 41 onto the hybrid material was evaluated in aqueous solution. The studies of pH (3.0–12.0), adsorbent concentration (0.5–5.0 g L−1), kinetic and adsorption equilibrium were investigated at 303 K. The kinetic data were best fitted to the pseudo‐second order kinetic model. Equilibrium studies showed that the hybrid material achieved a maximum adsorption capacity of 205.3 mg g−1. The large amount of solid waste generated from wine production represents a serious impasse for wineries regarding its storage and disposal, from both ecological and economical points of view. Alternatively, this agricultural solid waste may represent a source of raw material to create new products, increasing the life cycle and adding value to the previously discarded material. In this work, grape stalk was employed as adsorbent for dye removal, promoting the reduction of environmental contamination. The results showed that it is a promising material to use as efficient eco‐friendly adsorbent for the treatment of wastewater.

Comparative study of biochar prepared from cow dung and sewage sludge and its application as an adsorbent for organic pollutants removal in water

“…4,5 On the other hand, dye adsorption is considered versatile, economical, easy to operate, and environmentally friendly. 6 Several adsorbents have been used successfully to eliminate dyes in wastewater effluents. 7 Commercially available adsorbents such as granular activated carbon have been shown to be effective for wastewater treatment due to the microporous structure, which gives it a high adsorption capacity.…”

Estudo da biossorção de cianeto de mercúrio gerado na mineração artesanal do ouro visando a descontaminação de águas residuais.

“…Isso indica que a adsorção é homogênea, com entalpia constante e que todos os sítios disponíveis para a adsorção possuem mesma afinidade para a adsorção (FOO; HAMEED, 2010). A Equação 9 representa a isoterma de adsorção para o modelo de Langmuir (AL-GHOUTI; DA 'ANA, 2020;BENVENUTI et al, 2020;CRINI;LICHTFOUSE, 2018;FOO;HAMEED, 2010).…”

“…Além disso, a relação adsorventeadsorvato também é uma condição a ser considerada, de forma que o calor de adsorção das camadas é reduzido linearmente com a cobertura do adsorvente (AL-GHOUTI; DA 'ANA, 2020;FOO;HAMEED, 2010;LIU, 2008;NASCIMENTO et al, 2014). A Equação 15 representa o modelo de Temkin (AL-GHOUTI; DA 'ANA, 2020;BENVENUTI et al, 2020;51 DADA et al, 2012;DE ANGELIS et al, 2017;FOO;HAMEED, 2010;LIU, 2008;NASCIMENTO et al, 2014).…”

“…O modelo de pseudoprimeira ordem é descrito pela Equação 18 (ABDOLALI et al, 2016;BENVENUTI et al, 2020;MENDOZA-CASTILLO;REYNEL-ÁVILA, 2017;FERREIRA et al, 2019;JACQUES et al, 2007). A Equação 19 é a forma linearizada do modelo (ABDOLALI et al, 2016;JACQUES et al, 2007;OFOMAJA, 2010).…”

“…No trabalho de Saikawe e Kaewsarn (2009), a adsorção de cádmio na casca de banana também ocorreu nos grupos carboxílicos e hidroxílicos. Outros biossorventes também foram avaliados para a adsorção de diferentes adsorvatos, apresentando semelhanças nos grupos funcionais que interagiram durante a adsorção(BENVENUTI et al, 2020;JACQUES et al, 2007).Celulose, pectina e lignina são as principais estruturas que formam a casca de banana. No entanto, mesmo havendo interação nessas três estruturas durante a adsorção das diferentes soluções avaliadas, foi possível verificar que o íon mercúrio teve comportamento diferenciado de ligação na superfície da casca de banana.…”