Synthesis and characterization of iodo polyurethane foam and its application in removing of aniline blue and crystal violet from laundry wastewater

Abstract

A new sorbent was prepared by treating polyurethane foam with HCl and replacing the amino functional groups with iodine atoms. The properties of iodo-polyurethane were studied with infrared, ultraviolet and visible spectroscopy, bulk density, pH ZPC and elemental and thermal analysis. Removal of aniline blue and crystal violet dyes from water with iodo-polyurethane were investigated with the batch technique. Maximum removal was achieved at pH 7-12. The effect of the initial dye concentration on the equilibrium adsorption from aqueous solutions with iodo-polyurethane was found to have a good correlation, with r 2 = 0.995 and an intercept of 0.039 when analyzed in the Langmuir and Freundlich isotherm models. The capacity of iodo-polyurethane for aniline blue and crystal violet were 0.24 and 0.45 mmol g −1 , respectively (188.9 and 183.6 mg g −1). The values of G and H were −7.7 kJ mol −1 and −26.1 kJ mol −1 , respectively, indicating that sorption is spontaneous and exothermic. The sorption rate of the dyes onto iodo-polyurethane was rapid, with 50% removal within 50 s. The pseudo-second order equation best described the kinetics of absorbed aniline blue and crystal violet (r 2 = 0.994). A modified equation (y = ax 0.n) was used to treat deviation from the Morris-Weber model for the sorption diffusion mechanism of crystal violet onto iodo-polyurethane. Use of iodo-polyurethane for removing aniline blue and crystal violet contamination from laundry wastewater is thus possible.

Kinetics, Thermodynamics, and Isothermic Evaluation in Sorption Study of Hazardous Dye Using Sodium Dodecylsulfate Physically Impregnated in Polyester‐Type Polyurethane Foam

“…The second step of film diffusion follows the pseudo‐first‐order kinetics, while intraparticle diffusion does not. At longer times, the adsorption process changes and the experimental data did not fit the pseudo‐first‐order equation, so pseudo‐second‐order kinetics model was applied: where the concentration of CV adsorbed at equilibrium and at time t is q e and q t (mol g −1 ), respectively, and K 2 is the pseudo‐second‐order rate constant (Moawed, Abulkibash, & El‐Shahat, ). If adsorption process follows the pseudo‐second order, a linear relationship is obtained between t / q t and t (Fig.…”

“…Studies have shown that if the plot of q t against t 1/2 (Fig. ) fits a straight line, intraparticle diffusion process is the rate controlling step of adsorption process (Table ) (Moawed et al, ; Wu, Tseng, & Juang, ). If the kinetic data fit this linear relationship, the slope could be used to obtain the rate constant for intraparticle transport using the following equation: where the amount of CV sorbed at time t (min) is q t (mol g −1 ), the rate constant of intraparticle transport is K d (mol gmin −1/2 ) and the intercept is C (mg g −1 ).…”

“…where the concentration of CV adsorbed at equilibrium and at time t is q e and q t (mol g −1 ), respectively, and K 2 is the pseudo-second-order rate constant (Moawed, Abulkibash, & El-Shahat, 2015). If adsorption process follows the pseudosecond order, a linear relationship is obtained between t/q t and t (Fig.…”

“…4 Kinetics study on the rate of adsorption of CV onto PUF that if the plot of q t against t 1/2 (Fig. 4) fits a straight line, intraparticle diffusion process is the rate controlling step of adsorption process (Table 2) (Moawed et al, 2015;Wu, Tseng, & Juang, 2009). If the kinetic data fit this linear relationship, the slope could be used to obtain the rate constant for intraparticle transport using the following equation:…”

Micro–Nanocomposites in Environmental Management

“…In addition, the foam could be regenerated many times without obvious decrease in the absorption capacity . In order to enhance the adsorption selectivity and efficiency for removal of organic dye from wastewater, Ke et al synthesized an attapulgite‐modified PU foam by the foaming technique . Attapulgite, as a natural adsorbent with high surface area and exchangeable cations, as well as reactive hydroxyl on its surface, can effectively absorb cations dyes from wastewater.…”