Use of sweet ‘Pêra’ peel as an adsorbent in the treatment of textile effluents

Abstract

The disposal of industrial wastewater into aquatic bodies without proper treatment can cause severe damage to the environment and human health. The objective of this study was to perform the drying of the sweet orange (Citrus sinensis L. Osbeck) peel cultivar Pêra and evaluate the viability of its use as biosorbent in the removal of a direct dye. Drying was carried out in an oven with air circulation at temperatures of 60 and 80 ºC. The mathematical models of Page, Henderson and Pabis, Logarithmic, Midilli and Two-term exponential were fitted to the moisture data as a function of time. The material was characterized by scanning electron microscopy, point of zero charge, and infrared spectroscopy. In the adsorption study, a complete 24 factorial design was used to analyze the influence of mass, initial concentration, solution pH and contact time on adsorbed quantity (qt) and removal percentage of the dye (R%). In the drying, the two-term exponential model fitted best to the experimental data. The characterization of the material indicated that the adsorbent has zero charge point of 3.5 and porous structure, and the infrared analysis indicated the presence of carboxylic and hydroxyl groups. In the adsorption, the adsorbed quantity of the dye increased under conditions of lower pH and biosorbent mass and higher initial concentration and contact time. The removal percentage of dye increases with higher biosorbent mass. The biosorbent used is a promising waste for the adsorption of the burgundy-16 dye.

Adsorção De Cobre Presente Em Solução Aquosa Por Adsorvente De Casca De Laranja Seco E Modificado Com Hcl. / Copper Adsorption Present in Aqueous Solution by Dry Orange Shell Adsorbent and Modified With HCL

“…O pH da solução é um parâmetro de grande importância no estudo da adsorção de metais, pois, tem influência direta na carga superficial do biossorvente, logo, a mudança de pH da solução, afeta o processo de adsorção através da dissociação dos grupos funcionais nos sítios ativos da superfície do biossorvente (BEN-ALI et al, 2017;NASCIMENTO et al, 2019). Nas condições de adsorção estudadas, avaliando a relação das variáveis (massa de adsorvente e concentração do adsorvato, pH e tempo de contato) na resposta qt obtida com o adsorvente modificado, a melhor condição experimental para os ensaios de adsorção de cobre foi de 40 mg. L -1 de Cu 2+, 0,2 g da massa do adsorvente, em pH 5 e tempo de contato de 40 min, obtendo-se a capacidade de adsorção igual 4,21 mg. g -1 como pode ser observado na Tabela 2.…”