Adsorptive removal of direct dyes by low cost rice husk: Effect of treatments and modifications

Abstract

In the present study, free, carboxymethyl cellulose (CMC)-immobilized, polyvinyl alcohol (PVA)-alginate immobilized and chemically treated rice husk biomass was used for the biosorption of Everdirect Orange-3GL and Direct Blue-67 dyes. Maximum biosorption capacity of free, immobilized and hydrochloric acid treated biomass was observed for both dyes at low pH. Comparative study of free, immobilized and HCl treated biomass showed that, the HCl treated biomass exhibited more biosorption capacity (29.98 and 37.92 mg/g) for Everdirect Orange-3GL and Direct Blue-67, respectively. Equilibrium time was less for HCl treated biomass when compared with immobilized biomass. The Langmuir type 1 and 2 models were best fitted to experimental data for free, CMC, polyvinyl alcohol-alginate immobilized and HCl treated biomass in case of Everdirect Orange-3GL, while the equilibrium data of Direct Blue-67 followed the Langmuir type 2 isotherm. Pseudo-second-order and Elovich kinetic models illustrated good fitness to all types of biomasses showing chemisorption nature of biosorption. The amount of dyes sorbed (mg/g) increased with increase in temperature. The values of Gibbs free energy (∆G°) showed that reaction was spontaneous at high temperature.

Sequestering Attributes of Typha Latifolia as a Low Cost Biosorbentfor the Removal of Reactive Dye (Db-K2rl) From Aqueous Media

“…The adsorption of DB-K 2 RL was increased from 58.36% to 78.62% (Fig. 4) with an increase in initial concentration of dye up to 50 ppm, after that it decreased even by increasing the initial concentration of dye (Safa and Bhatti 2011).Initially at lower concentration of dye number of sites on sorbent were greater, therefore percentage removal of dye was increased (Aksu and Kabasakal 2004). At higher concentration, active adsorption sites were insufficient and adsorption rate decreased (Orfaco et al, 2006).…”

“…Figure 3: Effect of amount of biosorbent on the sorption of DB-K 2 RL on T. latifolia leaves ii) Effect of dye concentration:The adsorption of DB-K 2 RL was increased from 58.36% to 78.62% (Fig.4) with an increase in initial concentration of dye up to 50 ppm, after that it decreased even by increasing the initial concentration of dye(Safa and Bhatti 2011).Initially at lower concentration of dye number of sites on sorbent were greater, therefore percentage removal of dye was increased(Aksu and Kabasakal 2004). At higher concentration, active adsorption sites were insufficient and adsorption rate decreased(Orfaco et al, 2006).The results reported by(Paola et al, 2004) revealed that the adsorption of 2,4-dichlorophenoxyacetic acid was fast at the initial stages of contact time and was slowed down near equilibrium due to high affinity of the interacting groups on the surface of the activated carbon, similar results were obtained in our study.…”

Synthesis and Characterization of Hydroxyethyl Cellulose Grafted with Copolymer of Polyaniline and Polypyrrole Biocomposite for Adsorption of Dyes

“…The optimal condition remained same i.e., pH, contact time (2 h), temperature (27 °C) and 150 rpm shaking speed. It was found that adsorption ability decreased with rise of HEC/PANI-PPy which is ascribed to aggregation of the adsorbent with concomitant rise in adsorbent concentration and decreasing availability of surface for adsorption [ 48 ].…”

Evaluating the Impact of Cellulose Extraction via Traditional and Ionosolv Pretreatments from Domestic Matchstick Waste on the Properties of Carboxymethyl Cellulose

“…Moreover, a survey of literature has disclosed that CMC has been produced by extracting cellulose from ample biosources like sago waste, wheat straw, rice straw, corn husk, rice husk, cotton linters, banana leaves, bagasse, and others . But the most common waste on the domestic level that is overlooked is matchstick (MS) waste made of bamboo.…”