Dye removal from wastewater by the cross‐linked blend nanofiber and homogenous surface diffusion modeling

Abstract

In this paper, the blend nanofiber (poly(vinyl alcohol) (PVA)/chitosan (CS)/diethylenetriamine (DETA)/ethylenediamine (EDA): PVA/CS/DETA/EDA) was prepared by electrospinning and cross‐linked by glutaraldehyde. The cross‐linked blend nanofiber by glutaraldehyde (CBNG) was characterized by FTIR and SEM. The homogenous surface diffusion model (HSDM) was used for expressing the dye adsorption on CBNG from colored wastewater. Experimental data were used to calculate the isotherm parameters as well as the kinetic parameters describing mass transfer resistances due to film diffusion (kf) and diffusion coefficient (Ds). The sum square error (SSE) values for the adsorption of Acid Red 18 (AR18), Direct Blue 78 (DB78), and Direct Red 23 (DR23) were 0.0221, 0.0632, and 0.0038, respectively. Thus, the experimental and theoretical data showed a good agreement. Dye removal by CBNG followed the Langmuir isotherm and pseudo‐second order kinetics models. Thermodynamic studies indicated dye adsorption onto the nanofiber was an endothermic, spontaneous, and physisorption process. © 2017 American Institute of Chemical Engineers Environ Prog, 36: 1634–1642, 2017

Solanum xanthocarpum Plant as a Potential Low Cost Adsorbent for the Removal of Methylene Blue from Aqueous Solutions

“…Sparks has reported that without spectroscopic evidences, it is very difficult to interpret sorption mechanisms simply from time dependent data . However, in the present study we suggest that the initial rate of reaction is controlled by the surface reaction, like adsorption and surface precipitation, in line with explanation given in the earlier sections on the basis of FTIR findings and SEM images after MB sorption, which are then changed to intraparticle diffusion into the pores of the biosorbent .…”

“…Figure shows the effect of temperature on the sorption of cationic MB by Solanum xanthocarpum fruit powder, where it is evident that by increasing the temperature of the system from 293 to 323 K, the uptake of MB increases both at pH 4 and 6, showing the sorption process to be endothermic. Similar increase in the sorption of cationic dyes and other cations from aqueous solutions, with increasing temperature has been reported in a number of previous studies . By increasing the temperature from 293 to 323 K, the sorption of MB increases drastically at pH 6, while at pH 4, there is a gradual increase in its sorption with increasing temperature and concentration.…”

“…It is evident from the Table that the rate constant k ad values are negative for Lagergren first order which have nothing to do with explanation of the rate of reaction, while the value of rate constant k in case of second order agree well in values of the literature for MB adsorption kinetics . Many researchers have correlated this observation in case of second order with the diffusionally controlled process . Sparks has reported that without spectroscopic evidences, it is very difficult to interpret sorption mechanisms simply from time dependent data .…”

“…The band at 2924 and 2853 cm −1 represents CH symmetric and asymmetric stretching of the bond of alkyl group of biomass , while the bands at 1746.7, 1644, and 1016 cm −1 are related to the CO or CC stretching of the hemicelluloses and lignin aromatic groups . Similarly, the smaller bands at 1400 and 1350 cm −1 are due to phenolic OH, CH, and SO 3 H groups, respectively . The weak band at 2310 cm −1 , represents a cluster of multiple small peaks may also be due to NH bending of amide group.…”

“…Due to increasing industrialization and urbanization of the modern world, large quantities of industrial wastewater containing toxic diazo dyes and heavy metal ions are pumped into our surrounding soil and water bodies . These highly toxic effluents coming out mostly from paper, textile, printing, cosmetics, leather, pulp, plastic, and electro‐plating industries into the soil biota have posed serious threats to living organisms including human beings and the ecosystem . Although heavy metals contamination of soil and waters is equally a serious problem, yet the dyes contamination in wastewater is one of the major causes of environmental pollution today.…”