The Coffee Residues and the Esparto Fibers as a Lignocellulosic Material for Removal of Dyes from Wastewater by Adsorption

Biosorption onto lignocellulosic products such as coffee residues and esparto fibers in natural and modified forms have been identified as a potential alternative to the existing biosorbents applied for dye removal from wastewater. The efficiency of each material has been discussed with respect to the operating conditions and the chemical modifications. The investigated thermodynamics and kinetics studies were exposed also in terms of equilibrium isotherms and fitted kinetic models. Moreover, the crucial role of the chemical structures of the cellulosic fibers as an affecting factor on the mechanism of the adsorption process was evaluated and compared. The different treatment methods showed an improvement in terms of removal and maximum adsorption capacity. In fact, in some cases the removal capacity can be increased to 99% and the maximum adsorption capacity can reach 67 mg/g. On the other hand, the different investigations showed that the study data fitted to the known model such as Langmuir isotherm and pseudo-second-order kinetic

New ion exchange membrane derived from sulfochlorated polyether sulfone for electrodialysis desalination of brackish water

The purpose of this work is to study the desalination of brackish water using a new ion exchange membrane, made from sulfochlorated polyethersulfone (Cl-PES), and crosslinked using aminated polyethersulfone (NH2-PES) as a crosslinking reagent. This membrane, named ClNH2 membrane, has been obtained by reaction between Cl-PES with 1.3 SO2Cl groups per monomer unit and 0.2 equivalent amount of NH2-PES. ClNH2 membrane has been characterized in terms of contact angle, transport number, intrinsic conductivity, and water uptake (as a function of temperature). Electrodialysis performances of the newly synthetized membranes have been measured using an electrodialysis cell at a laboratory scale and compared to commercial membranes. All the experiments have been performed using synthetic brackish water solutions prepared from sodium chloride salts with different concentrations (varying from 0.5 to 5.0 g/L). The concentration of different water samples obtained has been found to be below the amount recommended by the World Health Organization (WHO) for drinking water.ERAS Labo; World Health Organizatio

Adsorption of congo red dye from aqueous solutions by prepared activated carbon with oxygen-containing functional groups and its regeneration

This study investigates the potential use of activated carbon prepared from coffee waste (CW) as an adsorbent for the removal of congo red dye from aqueous solution. The oxygen-containing groups of activated carbon prepared from CW play an important role in dyes ions adsorption onto activated carbon prepared from CW. The activated carbon is characterized by scanning electron microscopy and Fourier transform infrared (FTIR) spectroscopy. Adsorption experiments were carried out as batch studies at different contact time, pH, and initial dye concentration. The dye adsorption equilibrium was attained after 120 min of contact time. Removal of dye in acidic solutions was better than in basic solutions. The adsorption of dye increased with increasing initial dye concentration. The equilibrium data were revealed that Langmuir model was more suitable to describe the congo red adsorption and demonstrated excellent reusability potential with desorption greater than 90% throughout six consecutive adsorption–desorption cycles. Experimental data founded that kinetics followed a pseudo-second-order equation. Thermodynamic study showed that the adsorption was a spontaneous and exothermic process. According to the FTIR analyses, hydrogen bonding and electrostatic interactions between dyes and oxygen-containing functional groups on activated carbon prepared from CW are dominant mechanisms for dye adsorption

Synthesis and characterization of alpha alumina-natural apatite based porous ceramic support for filtration application

The present study reported the synthesis of low-cost ceramic membrane supports. They were prepared by an extrusion method using alumina/natural apatite blends and further consolidated by heat treatment. The chemical composition, structure and particle size of the starting materials were analyzed. The effect of the natural apatite content, as sintering agent, on the microstructure, porosity, flexural strength and linear shrinkage of the prepared supports were studied as a function of sintering temperature. The microstructure exhibited that the sintering temperature decreased with the increment of the apatite content. The porosity and the pore size were controlled by the sintering temperature and the apatite amount added to the starting mixture. The mechanical strength and the linear shrinkage increased with increasing the apatite and the firing temperature. The sample selected for filtration displayed good porosity (45.38%) and pore size of 1.35 mu m giving a high perme-ability 959.64 h(-1) m(-2) bar(-1)