Cadmium Removal from Contaminated Water Using Polyelectrolyte-Coated Industrial Waste Fly Ash

Abstract

Fly ash (FA) is a major industrial waste generated from power stations that add extra cost for proper disposal. Recent research efforts have consequently focused on developing ways to make use of FA in environmentally sound applications. This study, therefore, investigates the potential ability of raw fly ash (RFA) and polyelectrolyte-coated fly ash (PEFA) to remove cadmium (Cd) from polluted water. Using layer-by-layer approach, functionalized fly ash was coated with 20 layers from 0.03% (v/v) of cationic poly(diallyldimethylammonium chloride) (PDADMAC) and anionic polystyrene sulfonate (PSS) solutions. Both surface morphology and chemical composition of the adsorbent (PEFA) were characterized using Field-Emission Scanning Electron Microscope (FE-SEM), X-Ray Diffraction (XRD), Fourier-Transform Infrared (FTIR), and X-Ray Fluorescence (XRF) techniques. The effects of pH, adsorbent dosage, contact time, initial contaminant concentration, and mixing rate of the adsorption of Cd were also studied in batch mode experiments. Results of the study revealed that a 4.0 g/L dosage of PEFA removed around 99% of 2.0 mg/L of Cd in 15 min at 150 rpm compared to only 27% Cd removal achieved by RFA under the same conditions. Results also showed that adsorption by PEFA followed both Langmuir and Freundlich models with correlation coefficients of 98% and 99%, respectively.

Adsorption of Ni2+ and Cd2+ from Water by Calcium Alginate/Spent Coffee Grounds Composite Beads

“…Cadmium is released to the environment in industrial processes such as smelting, alloy manufacturing, and pesticides. Anthropogenic activities such as improper disposal of unused paints, fertilizers, and Ni/Cd batteries are also sources of cadmium contamination [2]. Cadmium affects cell proliferation, differentiation, and apoptosis, therefore interacting with DNA repair mechanisms, the generation of reaction oxygen species (ROS) and the induction of apoptosis [3].…”

Poly (N-vinyl Imidazole)/Nitrogen-Doped Graphene Quantum Dot Hydrogel Adsorbent With Remarkable Capability for Metal Ion Removal From Aqueous Systems

“…Moreover, the sudden increase and decrease in the removal efficiency as observed in Fig. 5 suggest an elaborate process of exchanging ions, sorption driven by physical forces, metal chelation, and trapping of ions in the internal sphere of the structural arrangement of the adsorbents [38].…”

“…Where (mg/L) is the equilibrium concentration of the metal ions in solution, (mg/g) is the amount of metal ions adsorbed at equilibrium. is the maximum adsorption capacity (mg/g) of the hydrogel and is the Langmuir constant related to adsorption energy (L/mg) [37,38]. The and are calculated from the slope and intercept of the linear plot of of against Fig.…”

“…The for metal ions is high, and it could be attributed to the presence of imidazole moieties, dicationic groups of DIL and carboxylic acid and amine groups of NGQDs in the hydrogel, which can be explained by their noncovalent interaction with the metal ions [34,[36][37][38]. The Langmuir isotherm constant ( ) is found to be 0.0105, 0.0069 and 0.0504 L/mg for V-D-G1-Cd, V-D-G1-Ni and V-D-G1-Cr, respectively, which predicts the strong coordinate covalent interaction between the metal ions and the adsorbent.…”

Is childhood obesity a result of toxic exposure to cadmium or malathion? An observational pilot Egyptian study

“…Both cadmium, which is found in wastewater, and malathion, a commonly used pesticide, have reported endocrine disrupting effects [2,5,6]. Both may be contributors to the obesity epidemic [2,7,8].…”