In-Depth Study of Heavy Metal Removal by an Etidronic Acid-Functionalized Layered Double Hydroxide

Abstract

Sorption methodologies play a pivotal role in heavy metal removal to meet the global requirements for uninterrupted access to drinkable water. Standard sorption technologies lack efficiency due to weak adsorbent–metal interaction. To this end, a layered cationic framework material loaded with phosphonate was first fabricated by a facile intercalation method to capture hazardous metals from an aqueous solution. To inquire the removal mechanisms, batch experiments, detection technologies, and simulation calculations were employed to study the interactions at the interface of clay/water. Specifically, the functionalized layered double hydroxide possessed excellent chelation adsorption properties with Zn2+ (281.36 mg/g) and Fe3+ (206.03 mg/g), in which model fitting results revealed that the adsorption process was chemisorption and monolayer interaction. Further, the interfacial interaction between the phosphonate and clay surface was evaluated by molecular dynamics simulation, and a new concept named the interaction region indicator was used to characterize weak interaction and coordinate bonds. The deep insight into the chelation mechanism was visually presented via the orbital interaction diagram. In addition, the regeneration of the spent adsorbent, adsorption column test, and acute toxicity analysis demonstrated that the synthesized material has immense potential in terms of practical usage for the treatment of toxic pollutants. These results provide a novel path for researchers to properly understand the adsorption behavior.

A Study of Copper (II) Ions Removal by Reverse Osmosis under Various Operating Conditions

“…Heavy metals such as copper should be eliminated from industrial wastewater before reaching the natural environment, and this can be accomplished through various treatment techniques including chemical precipitation [4], a flotation process [5,6], ion exchange [7,8], electrochemical treatment [9,10], adsorption [11][12][13][14][15] and membrane filtration [16][17][18][19][20][21][22][23]. Each of these methods has disadvantages and some limitations.…”

Synthesis and Micromechanistic Studies of Sensitized Bentonite for Methyl Orange and Rhodamine-B Adsorption from Wastewater: Experimental and DFT-Based Analysis

“…The removal rate was higher at the early stage because there were more empty spaces, which increased adsorption. At equilibrium conditions, up to 50 mg/L concentration of dye could be best removed ( Figure 5 b) [ 35 ].…”

Ab initio molecular dynamics simulations on the adsorption of 1-hydroxyethane-1,1-diphosphonic acid on the iron (100) surface

“…IRI method [51][52][53] can be used to graphically investigate chemical bonds and weak interactions. The definition of the IRI function is as follows: where a is an adjustable parameter, and a = 1.1 is adopted for standard definition of IRI.…”