The solid-liquid interface reaction between phosphate rock (PR) and metals (Pb, Cu, and Zn) was studied. Phosphate rock has the highest affinity for Pb, followed by Cu and Zn, with sorption capacities of 138, 114, and 83.2 mmol/kg PR, respectively. In the Pb-Cu-Zn ternary system, competitive metal sorption occurred with sorption capacity reduction of 15.2%, 48.3%, and 75.6% for Pb, Cu, and Zn, respectively compared to the mono-metal systems. A fractional factorial design showed the interfering effect in the order of Pb>Cu>Zn. Desorption of Cu and Zn was sensitive to pH change, increasing with pH decline, whereas Pb desorption was decreased with a strongly acidic TCLP extracting solution (pH = 2.93). The greatest stability of Pb retention by PR can be attributed to the formation of insoluble fluoropyromorphite [Pb(10)(PO(4))(6)F(2)], which was primarily responsible for Pb immobilization (up to 78.3%), with less contribution from the surface adsorption or complexation (21.7%), compared to 74.5% for Cu and 95.7% for Zn. Solution pH reduction during metal retention and flow calorimetry analysis both supported the hypothesis of retention of Pb, Cu, and Zn by surface adsorption or complexation. Flow calorimetry indicated that Pb and Cu adsorption onto PR was exothermic, while Zn sorption was endothermic. Our research demonstrated that PR can effectively remove Pb from solutions, even in the presence of other heavy metals (e.g. Cu, Zn).

https://digitalcommons.calpoly.edu/cgi/viewcontent.cgi?article=1014&context=ersc_fac

Understanding the Mechanisms of Lead, Copper, and Zinc Retention by Phosphate Rock

Preparation of chitosan composite film reinforced with cellulose isolated from oil palm empty fruit bunch and application in cadmium ions removal from aqueous solutions.

Porous crystalline materials such as covalent organic frameworks (COFs) have gained tremendous popularity in multidisciplinary areas of science and technology. In this study, for the first time, we report a covalent triazine-based framework (CTF-1) as an efficient adsorbent for the removal of Cd2+ from aqueous solutions. CTF-1 offered excellent stability under extreme conditions for the effective removal of cadmium cations (Cd2+) from aqueous solutions. CTF-1 was first synthesized through an ionothermal method and then characterized by XRD, SEM, TEM and BET surface area measurements to confirm its highly crystalline and microporous nature. Batch adsorption experiments were systematically conducted under a wide range of pH, metal ions concentration, adsorbent dosage and contact time to investigate kinetics, thermodynamics and adsorption properties of CTF-1 towards Cd2+ ions removal. The pseudo-second-order model showed good fitting to experimental data, whereas Langmuir and D–R isotherms confirmed the chemical nature of the adsorption. Similarly, thermodynamic parameters indicated the adsorption to be spontaneous and endothermic. Furthermore, our simulation results showed that CTF-1 possess uniform distribution of negative charge along the framework, making it an ideal candidate for the adsorption of cations together with the high stability in both acidic and basic pH. The strategies adopted in this study will open a new avenue to design novel nanoporous functional materials for next generation adsorbents.

Adsorptive removal of Cd2+ from aqueous solutions by a highly stable covalent triazine-based framework

Sequestration of heavy metal ions by Methionine modified bentonite/Alginate (Meth-bent/Alg): A bionanocomposite

Immobilization of cadmium by hydroxyapatite converted from microbial precipitated calcite.

Removal of Cadmium from Water Using Natural Phosphate as Adsorbent

Adsorption process is being widely used by various researchers as an effective process of advanced waste water treatment of industrial effluent containing metals. The present work involves an investigation of the use of natural phosphate (NP), which being locally abundant and cheap material in Morocco, as adsorbent for removal of cadmium from aqueous solutions. .The kinetic of Cadmium on natural phosphate adsorption efficiency and adsorption process were evaluated and analyzed using Langmuir and Freundlich model of adsorption equilibrium. The effects of various experimental parameters, such as initial cadmium concentration, contact time were investigated. The natural phosphate had the monolayer adsorption capacity to 26mg/g at pH of 5.0. Adsorption measurements show that the process is very fast and physical in nature. The extent of the cadmium removal increase with decrease in the initial concentration. These results show that natural phosphate is a good adsorbent for cadmium from aqueous solutions and could b e used as a purifier for water and wastewater.

"SYMPHOS 2013", 2nd International Symposium on Innovation and Technology in the Phosphate Industry Removal of Cadmium from water using Natural phosphate as Adsorbent

O. Zidani

Papers

Removal of Cadmium from Water Using Natural Phosphate as Adsorbent

"SYMPHOS 2013", 2nd International Symposium on Innovation and Technology in the Phosphate Industry Removal of Cadmium from water using Natural phosphate as Adsorbent