Scavenging fluoride from the aqueous system with porous organometallic three-dimensional architecture: An emerging adsorbent

Simultaneous adsorption of ciprofloxacin drug and methyl violet dye on boron nitride nanosheets: experimental and theoretical insights

In this study, hexagonal boron nitride (BN) with a sheet-like morphology is successfully synthesized by reacting borax (Na2B4O7·10H2O) and urea (CO(NH2)2) powders in air via a facile microwave-assisted method within a short reaction time (15 min). The as-prepared product is structurally characterized via Fourier transformation infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FESEM), energy dispersion X-ray analyzer (EDX), transmission electron microscopy (TEM), and Brunauer-Emmett-Teller (BET) surface area measurements. The adsorption process of methyl violet (MV) as a model of organic dyes and ciprofloxacin (CIP) as a model of antibiotics onto the boron nitride nanosheets has been experimentally and theoretically studied. The BN nanosheets exhibit the maximum adsorption capacity of 320.94 mg g-1 for MV dye and 266.29 mg g-1 for CIP antibiotic. The Freundlich isotherm model was suitable to describe the adsorption equilibrium isotherm data and the pseudo second-order model reflected the adsorption kinetics well. The calculated thermodynamic parameters show that the adsorption process is spontaneous under the measured conditions. The adsorption of CIP, MV and CIP + MV molecules on the surface of BN has been investigated through DFT calculations. The charge transfer and high adsorption capacity demonstrate the potential of BN nanosheets as an adsorbent for the simultaneous removal of MV dye and CIP drug from contaminated water.

One-pot facile approach to design an efficient macro-porous polymeric matrix to remediate Hg(II)and Pb(II) from aqueous medium and its performance evaluation study by mathematical modelling

In the present scenario discharge of heavy-metal ions into water bodies is a global threat that is causing serious health hazards even in low concentrations. Thus, in order to remediate the heavy-metal [Hg(II) and Pb(II)] toxicity, an organic-inorganic hybrid functional porous metallo-polymeric network i. e, poly(Zirconyl methacrylate-co-1-vinyl imidazole) (pZrVIm) was fabricated via one-pot facile synthesis approach. The pZrVIm architecture has shown high removal efficiency for Hg(II) and Pb(II) aqueous medium even in extremely low quantities. Advanced instrumental techniques were used to characterize the structural and morphological characteristics of pZrVIm. Different experimental variables i.e., reaction time, pH, initial feed concentration, co-ion effects etc. were explored to examine adsorption behaviour. The maximum adsorption capacities (q_max) of pZrVIm5 were calculated as 168.06 and 162.34 mg g^-1 for Hg(II) and Pb(II) respectively by the Langmuir isotherm model. Data from isotherms showed that monolayer adsorption on a homogeneous surface is the rate-limiting stage and followed pseudo-second-order kinetic process. The Artificial Neural Network (ANN) modelling was used to validate kinetics and isotherm data which revealed high accuracy of the model with correlation coefficient values (R = 0.99). Various types of isotherm models such as Langmuir, Freundlich, Dubinin-Radushkevich, Temkin, Redlich-Peterson, Toth and Koble-Corigen have been studied to determine the adsorption phenomena. The pore diffusion model revealed breakthrough time of 91 h and 84 h, Hg(II) and Pb(II) with the feed concentration of 15 mg L^-1 respectively. The study revealed that pZrVIm5 has great potential for heavy metal ions remediation for water treatment.

Synchronous Removal of Arsenic and Fluoride from Aqueous Solution: A Facile Approach to Fabricate Novel Functional Metallopolymer Microspheres

Concurrence of arsenic (As) and fluoride (F-) ions in groundwater is a serious concern due to their fatal effects. Herein, an attempt was made to fabricate quaternized poly(zirconyl dimethacrylate-co-vinylbenzyl chloride)] (ZrVBZ), a metallopolymeric microsphere in three-dimensional shape with a porous texture. The synthesized ZrVBZ was utilized for the synchronal removal of As and F- from water. Techniques such as Fourier transform infrared spectroscopy, 13C-nuclear magnetic resonance, scanning electron microscopy, and Brunauer-Emmett-Teller surface area were used to characterize the ZrVBZ. The maximum adsorption capacity of ZrVBZ for both fluoride and arsenic (q max F-: 116.5 mg g-1, q max As(V): 7.0 mg g-1, and q max As(III): 6.5 mg g-1) at given experimental conditions (adsorbents' dose: 0.250 g L-1, feed of F-: 50 mg L-1, As(V)/As(III): 2000 μg L-1, and pH: 7.0 ± 0.2) was ascribed to the porous spherical architecture with dual functional sites to facilitate adsorption. The adsorption followed pseudo-second-order kinetics with a correlation coefficient of 0.996, 0.997, and 0.990 for F-, As(V), and As(III), respectively. The isotherm data fitted to the Langmuir isotherm model, and the maximum capacity was 121.5, 7.246, and 6.68 mg g-1 for F-, As(V), and As(III), respectively. The results of this study indicated that ZrVBZ could be used as an effective adsorbent for the simultaneous removal of F-, As(V), and As(III) from an aqueous medium.

Adsorption of cupric, cadmium and cobalt ions from the aqueous stream using the composite of iron(II,III) oxide and zeolitic imidazole framework-8

In recent research, the composite of Fe₃O₄ and metal-organic frameworks have shown great potential in removing potentially toxic metals from water. We conducted the adsorption studies of potentially toxic metal ions (Cu²⁺, Co²⁺ and Cd²⁺) using the composite of Fe₃O₄ and zeolitic imidazole framework-8 (Fe₃O₄@ZIF-8) for the first time. The solvothermal technique was used to synthesize the Fe₃O₄. The magnetic ZIF-8 offers high thermal stability, greater adsorption surface, good removability, and high chemical and thermal stability. Characterization techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR) were used to characterize the synthesized samples. The SEM and XRD results revealed the high purity and structural integrity of ZIF-8 crystallites. To remove potentially toxic metals (Cu²⁺, Co²⁺ and Cd²⁺), the influence of adsorbent dosage, contact time, pH, and adsorbate concentration on the adsorption performance of Fe₃O₄@ZIF-8 was investigated. The Langmuir isotherm accurately represented the adsorption processes, with absorption magnitudes of Fe₃O₄@ZIF-8 determined to be 46.82 mg g^-1, 71.29 mg g^-1 and 54.49 mg g^-1 for Cu²⁺, Co²⁺ and Cd²⁺, respectively. According to the adsorption mechanism analysis, the primary Cu²⁺, Co²⁺ and Cd²⁺ removal methods of Fe₃O₄@ZIF-8 were ion exchange and coordination bonds. The uptake capacity of Cu²⁺, Co²⁺ and Cd²⁺ solution by Fe₃O₄@ZIF-8 were not significantly affected by the presence of counter ions. The material exhibited superior regenerative properties for Cu²⁺, Co²⁺ and Cd²⁺ ions from water for up to three cycles. This study concluded that the Fe₃O₄@ZIF-8 could be a viable candidate for eliminating potentially toxic metals (Cu²⁺, Co²⁺ and Cd²⁺).