Removal of crystal violet from aqueous solutions using functionalized cellulose microfibers: a beneficial use of cellulosic healthcare waste

Abstract

In this research, preparation of functionalized cellulosic microfibers (FCMFs) was proposed as a beneficial use of cellulosic healthcare wastes for removal of crystal violet from aqueous solutions. The functionalization process was performed using sulfonation reaction by chlorosulfonic acid. The results of scanning electron microscopy revealed a significant deformation in fibrous structure of cellulose as a result of sulfonation process. The functionalization of cellulosic fibers was confirmed by investigation of FTIR spectra of cotton and FCMFs. The charge density of FCMFs was calculated from its sulfur content which was measured by CHNS elemental analyzer. The influence of factors affecting the adsorption process such as pH, salt content, contact time, initial dye concentration and temperature were examined. The adsorption capacity was increased by increasing the salt content and temperature. The equilibrium was achieved after 60 min of mixing. The equilibrium adsorption data were well described by Freundlich, Redlich-Peterson isotherms. The maximum adsorption capacity was found to be 872 mg g -1 . The adsorption kinetic data were well fitted to pseudo-second-order and Elovich kinetic models. Thermodynamic parameters indicated that the adsorption process was spontaneous and endothermic in nature. The residual root-mean-square error (RMSE), average absolute relative error (AARE), cross-correlation coefficient (CCC, R) and chi-square test (χ2) were used to evaluate the fitting of the adsorption isotherms and kinetic models to the experimental results. The saturated adsorbent was regenerated by acid washing (HCl, 1 mol L -1 ) and removal efficiency was decreased slightly in each batch adsorption/regeneration cycle.

Graphene dispersed cellulose microfibers composite for efficient immobilization of hemoglobin and selective biosensor for detection of hydrogen peroxide

“…Where Q is the total charge, n is the number of electrons transferred in the redox reaction, F is the Faraday constant, and A is the electrochemically active surface area of the biosensor. The obtained Ivalue of the biosensor is higher than that of previously reported for Hb immobilized on nanomaterial modified electrodes [34][35][36][37], and indicates a greater efficiency of Hb molecules adsorption on the composite electrode surface. We have also performed CV to determine the effect of scan rate (ranging from 50 to 1000 mV/s) on the electrochemical redox behavior of the Hb immobilized GR-CMF modified electrode.…”

New highly hydrated cellulose microfibrils with a tendril helical morphology extracted from agro-waste material: application to removal of dyes from waste water

“…The Langmuir isotherm model ( eqn (8) ) assumes that the adsorption is monolayer onto identical active sites of adsorbent with uniform adsorption energies and without lateral interaction and steric hindrance between the adsorbed molecules. 48 It can be expressed in the linear form as: where C e (mg L −1 ) is the equilibrium concentration of MB, q e (mg g −1 ) and q max (mg g −1 ) the equilibrium and maximum adsorption capacities, respectively, and k L is the Langmuir equilibrium constant.…”

“…The Freundlich isotherm model ( eqn (9) ) assumes that the adsorption is multi-layered and that the adsorption on surface is non-ideal and reversible, which is not restricted to the formation of monolayer coverage. 48 It can be expressed in the linear form as: where, k F (L g −1 ) is the adsorption coefficient, 1/ n is a constant related to the surface heterogeneity, and q e (mg g −1 ) and C e (mg L −1 ) are the equilibrium adsorption capacity and the equilibrium MB concentration, respectively.…”

“…The Langmuir isotherm model (eqn (8)) assumes that the adsorption is monolayer onto identical active sites of adsorbent with uniform adsorption energies and without lateral interaction and steric hindrance between the adsorbed molecules. 48 It can be expressed in the linear form as:…”

“…The Freundlich isotherm model (eqn (9)) assumes that the adsorption is multi-layered and that the adsorption on surface is non-ideal and reversible, which is not restricted to the formation of monolayer coverage. 48 It can be expressed in the linear form as:…”