Application of cupuassu shell as biosorbent for the removal of textile dyes from aqueous solution

Abstract

The cupuassu shell (Theobroma grandiflorum) which is a food residue was used in its natural form as biosorbent for the removal of C.I. Reactive Red 194 and C.I. Direct Blue 53 dyes from aqueous solutions. This biosorbent was characterized by infrared spectroscopy, scanning electron microscopy, and nitrogen adsorption/desorption curves. The effects of pH, biosorbent dosage and shaking time on biosorption capacities were studied. In acidic pH region (pH 2.0) the biosorption of the dyes were favorable. The contact time required to obtain the equilibrium was 8 and 18 h at 298 K, for Reactive Red 194 and Direct Blue 53, respectively. The Avrami fractionary-order kinetic model provided the best fit to experimental data compared with pseudo-first-order, pseudo-second-order and chemisorption kinetic adsorption models. The equilibrium data were fitted to Langmuir, Freundlich, Sips and Radke-Prausnitz isotherm models. For both dyes the equilibrium data were best fitted to the Sips isotherm model.

Adsorptive removal of reactive dyes from aqueous solution using activated carbon synthesized from waste biomass materials

“…Also, a part of reactive dye is hydrolyzed due to the alkali used in the dye bath which is unable to be fixed onto the cotton textile. Removal of dyes from wastewater is important because they are recalcitrant and hinder photosynthesis of aquatic plants and some of them are also toxic, carcinogenic and/or mutagenic (Allegre et al 2006;Cardoso et al 2011).…”

Application of AzollaFiliculoides Biomass in Acid Black 1 Dye Adsorption from Aqueous Solution

“…The adsorbent dose is another parameter that can influence the dye removal efficiency. As it mentioned, the dye removal increased with increasing the adsorbent dosage up to 10 mg/L which it can be due to the increasing the available adsorption sites for dye molecules; however the amount of adsorbed AB1 per unit mass of adsorbent (qe) decreased which it is observed in several studies (8,15,32). As it was observed the AB1 removal efficiency decreased from 96% to 30% for initial dye concentration of 25 there is an inverse relationship between initial dye concentration and dye removal percentage which it is agreed with the previous studies (33,34).…”

Otimização do processo de remoção do corante preto de remazol B por uso de biomassa mista de Aspergillus niger van Tieghem, 1867 (Ascomycota: Trichocomaceae) e Pennisetum purpureum Schumach., 1827 (Poales: Poaceae)

“…Os resultados ainda apontam que o processo não é favorecido pelo aumento do pH, isto é, em soluções mais acidas há uma melhor remoção, pois, a biossorção de corantes é influenciada pela carga superficial do material e pelo grau de ionização do corante (Cardoso et al, 2011).…”

“…Mesmo assim, o grupo sulfônico presente no corante preserva a sua forma aniônica já que seu pK a é inferior a 1. Essa interação de cargas (positivas e negativas) sugere que a biossorção ocorra via grupos protonados do material com grupos aniônicos do PRB (Cardoso et al, 2011). Já com o aumento do pH da solução, embora o corante permaneça na forma aniônica, deverá haver uma diminuição de sítios protonados na superfície do biossorvente, ocasionando a diminuição da capacidade biossortiva devido ao aumento e repulsão de cargas negativas (Kumar e Barak, 2013).…”

“…Os corantes têxteis utilizados atualmente são compostos orgânicos sintéticos, cuja finalidade é colorir fibras sintéticas ou naturais. Normalmente, a estrutura molecular destes corantes sintéticos apresenta dois constituintes principais: o grupo cromóforo, responsável pela coloração da fibra; e outro grupo funcional, responsável pela fixação na fibra dos tecidos (Cardoso et al, 2011;Kunz, et al, 2002;Teli, 2016). Esses compostos podem ser classificados de acordo com sua estrutura química e pelo método de fixação na fibra têxtil.…”