Ionic liquid [bmim] [TFSI] templated Na-X zeolite for the adsorption of (Cd2+, Zn2+), and dyes (AR, R6).

1-butyl-3-methylimidazolium bis(triflouromethylsufonyl)imide functionalization to Na-X zeolite (IFZ) is the primary goal of this study in order to evaluate its ability to remove heavy metals (Cd2+), (Zn2+), dyes Rhodamine 6G (R6), and Alizarin Red S (AR) from aqueous streams. IFZ was thoroughly examined using analytical techniques XRD, BET, FE-SEM, and FTIR, to better understand its physical and chemical properties. The surface area and the volume of pores (IFZ; 19.93 m2/g, 0.0544 cm3/g) were reduced in comparison to the parent zeolite (Na-X; 63.92 m2/g, 0.0884 cm3/g). According to SEM, the crystal structure of the zeolite (Na-X) has not been significantly altered by XRD analysis. The mechanism, kinetics, isotherms, and thermodynamic properties of adsorption were all studied using batch adsorption experiments under various operating conditions. IFZ adsorbs dyes (AR; 76.33 mg/g, R6; 65.85 mg/g) better than metal ions (Cd2+; 30.68 mg/g, Zn2+; 41.53 mg/g) in acidic conditions. The Langmuir isotherm and pseudo-second order models were found to be the most accurate models for equilibrium data. Adsorption is endothermic and spontaneous, as revealed by the thermodynamics of the process. The IFZ can be used in three (Cd2+), two (Zn2+), four (AR), and five (R6) cycles of desorption and regeneration. For these reasons, IL-modified zeolite can be used to remove multiple types of pollutants from water in one simple step.

Adsorption of Reactive Red 195 from aqueous medium using Lotus (Nelumbo nucifera) leaf powder chemically modified with dimethylamine: characterization, isotherms, kinetics, thermodynamics, and mechanism assessment.

NOVELTY STATEMENT: In the modern era, dyes are inevitable and their surging usage leads to colossal contamination of aqueous streams, thereby threatening both the land and aquatic species. One among such dye is anionic Reactive Red 195 (RR 195), and traceable even at minute concentrations of aqueous streams, posing a severe threat to living species. Moreover, RR 195 is highly recalcitrant offering resistance to biodegradation due to the presence of an azo (-N=N-) group within its structure. Thus, there is a definite need to address the issue of eliminating RR 195 from industrial wastewater effluents. In lieu of this, the primitive objective of this study is to test the effectiveness of the natural adsorbent lotus leaf (Nelumbo nucifera) for the selective sorption of RR 195 from the aqueous stream. Although ample literature is available on the direct utilization of lotus leaf as adsorbent, yet no study was performed on the chemical modification (dimethylamine) of the aforementioned adsorbent. Hence, an attempt has been made in this direction to add a new sorbent into the adsorbents database.

Removal of anionic (Acid Yellow 17 and Amaranth) dyes using aminated avocado (Persea americana) seed powder: adsorption/desorption, kinetics, isotherms, thermodynamics, and recycling studies.

Aminated avocado seed powder (AASP)-an eco-friendly novel adsorbent has been used for the removal of Acid Yellow 17 (AY 17) and Amaranth (AMR) from an aqueous phase. The AASP (before and after adsorption) was systematically characterized by different analytical techniques such as FT-IR, FESEM, EDX, and N2 adsorption-desorption analysis. Non-linear form of various kinetic (PFO and PSO) and isotherm (Langmuir and Freundlich) models were used to examine the adsorption behavior of AY 17 and AMR onto AASP. The adsorption of AY 17 and AMR onto AASP was well illustrated by the PSO kinetic model and Langmuir isotherm models. At 303 K, the maximum adsorption capacities (obtained from the Langmuir) of the AASP for AY 17 and AMR was 42.7 and 89.2 mg/g, respectively. The AY 17 and AMR adsorption was strongly pH-dependent with an optimum pH value of 2.0. Activation energy was calculated as 12.3 and 16.3 kJ/mol for AY 17 and AMR respectively, suggesting physical adsorption. The positive values of ΔGo and ΔHo indicated that the adsorption process of AY 17 and AMR onto AASP was non-spontaneous and endothermic. The negligible loss of adsorption capacity and excellent regeneration of AASP were observed for the five cycles. Statement of novelty: The present research majorly focused on the synthesis of adsorbent from Avocado seed for the removal of Acid Yellow 17 and Amaranth anionic dyes from aqueous solution. Although the literature is available on direct seed powder as adsorbent, to the best of our knowledge, no chemical modified adsorbent synthesis was not available. Hence, to fill the gap in the literature, we chose the following study that significantly enhanced the adsorption efficiency of the selected anionic dyes.

Adsorptive removal of anionic dye (Reactive Black 5) from aqueous solution using chemically modified banana peel powder: kinetic, isotherm, thermodynamic, and reusability studies.

The removal of Reactive Black 5 (RB5) using chemically modified banana peel powder (CMBPP) from aqueous solution was dealt with in the present investigation. Factors affecting the adsorption of RB5 (like pH solution, agitation speed, initial concentration of RB5, contact time and temperature) were investigated. FTIR, SEM-EDX, BET and Elemental analysis characterized the adsorbent material. Adsorption kinetic results evaluated by non-linear pseudo-second-order model was fitted well and showed good correlation with the experimental data than the pseudo-first-order model. The experimental equilibrium data evaluated by non-linear Langmuir, Freundlich, Dubinin-Radushkevich (D-R), and Temkin equations and the experimental data were well described by the Langmuir isotherm model. Langmuir monolayer sorption capacity of RB5 onto CMBPP was observed at pH 3.0 (211.8 mg/g). The values of thermodynamic parameters revealed that the sorption process was feasible, spontaneous, endothermic, and physisorption in nature, i.e. (ΔG° <0, ΔH° > 0, and ΔS° > 0). Desorption studies reveal that the maximum recovery of RB5 when 0.1 M NaOH solution used as a desorbent. The CMBPP also exhibited excellent regeneration efficiency for the five cycles of successive adsorption-desorption. The results exposed that CMBPP could use as a prospective adsorbent material for the removal of RB5 from aqueous media.

Removal of anionic dyes (Reactive Black 5 and Congo Red) from aqueous solutions using Banana Peel Powder as an adsorbent.

The adsorption characteristics of Reactive Black 5 (RB5) and Cong Red (CR) onto Banana Peel Powder (BPP) from aqueous solution were investigated as a function of pH, contact time, initial dye concentration and temperature. The BPP was characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) analysis. FTIR results revealed that hydroxyl (-OH), amine (-NH) and carboxyl (-CË­O) functional groups present on the surface of BPP. The SEM results show that BPP has an irregular and porous surface morphology which is adequate for dye adsorption. The equilibrium data were analyzed using Langmuir and Freundlich isotherm models. Experimental results were best represented by the Langmuir isotherm model. The adjustments of models were confirmed by the Chi-square (χ2) test and the correlation coefficients (R2). The maximum monolayer adsorption capacities of RB5 and CR on BPP calculated from Langmuir isotherm model were 49.2 and 164.6mg/g at pH 3.0 and 298K. Experimental data were also tested in terms of adsorption kinetics using pseudo-first-order and pseudo-second-order kinetic models. The results showed that the adsorption processes of both RB5 and CR followed well pseudo-second-order kinetic models. The calculated thermodynamic parameters ΔG°, ΔH° and ΔS° showed that the adsorption of RB5 and CR onto BPP was feasible, spontaneous and endothermic in the temperature range 298-318K. The RB5 and CR were desorbed from BPP using 0.1M NaOH. The recovery for both anionic dyes was found to be higher than 90%. Based on these it can be concluded that BPP can be used as an effective, low cost, and eco-friendly adsorbent for CR removal than RB5 from aqueous solution.

Equilibrium isotherms, kinetics, and thermodynamics studies for congo red adsorption using calcium alginate beads impregnated with nano-goethite.

The present study is concerned with the batch adsorption of congo red (CR) from an aqueous solution using calcium alginate beads impregnated with nano-goethite (CABI nano-goethite) as an adsorbent. The optimum conditions for CR removal were determined by studying operational variables viz. pH, adsorbent dose, contact time, initial dye ion concentration and temperature. The CABI nano-goethite was characterized by Fourier transform infrared spectroscopy (FTIR), X- ray diffraction (XRD) and Scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) analysis. The CR sorption data onto CABI nano-goethite were described using Langmuir, Freundlich, Dubinin-Radushkevich and Temkin isotherm models. The results show that the best fit was achieved with the Langmuir isotherm model. The maximum adsorption capacity (181.1mg/g) of CR was occurred at pH 3.0. Kinetic studies showed that the adsorption followed a pseudo-second-order model. Desorption experiments were carried out to explore the feasibility of regenerating the adsorbent and the adsorbed CR from CABI nano-goethite. The best desorbing agent was 0.1M NaOH with an efficiency of 94% recovery. The thermodynamic parameters ΔG°, ΔH°, and ΔS° for the CR adsorption were determined by using adsorption capacities at five different temperatures (293, 303, 313, 323 and 303K). Results show that the adsorption process was endothermic and favoured at high temperature.

Cytotoxic and Infection-Controlled Investigations of Novel Dihydropyridine Hybrids: An Efficient Synthesis and Molecular-Docking Studies.

A sequence of novel 1,4-dihydropyridines (DHP) and their hybrids was developed using a multicomponent strategy under environmentally benign conditions. In addition, computational studies were performed, and the ligand-protein interactions calculated in different bacteria and two fungal strains. Para-hydroxy-linked DHP (5f) showed the best binding energies of 3.591, 3.916, 8.499 and 6.895 kcal/mol against various pathogens used and other substances received a good docking score. The pathogen resistance potential of the synthesized targets against four bacteria and two fungi showed that whole DHP substances exhibit different levels of resistance to each microorganism. Gram-positive bacteria, which are highly sensitive to all molecules, and the MTCC-1884-encoded fungus strongly rejected the studied compounds compared to comparator drugs. In particular, the 5f candidate showed remarkable antimicrobial activity, followed by the substances 5a, 5b, 5j, 5k and 5l. Furthermore, MIC and MBC/MFC properties showed that 5f had a minimum bacterial concentration of 12.5 µg/mL against E. coli and against two fungal pathogens, with its killing activity being effective even at low concentrations. On the other hand, whole motifs were tested for their cytotoxic activity, revealing that the methoxy and hydroxy-linked compounds (5h) showed greater cytotoxic potency, followed by the two hydroxy linked compounds (5d and 5f). Overall, this synthetic approach used represents a prototype for future nature-favored synthesis methods and these biological results serve as a guide for future therapeutic drug research. However, the computer results play an important role in the further development of biological experiments.

Hollow-Architected Heteroatom-Doped Carbon-Supported Nanoscale Cu/Co as an Enhanced Magnetic Activator for Oxone to Degrade Toxicants in Water.

Even though transition metals can activate Oxone to degrade toxic contaminants, bimetallic materials possess higher catalytic activities because of synergistic effects, making them more attractive for Oxone activation. Herein, nanoscale CuCo-bearing N-doped carbon (CuCoNC) can be designed to afford a hollow structure as well as CuCo species by adopting cobaltic metal organic frameworks as a template. In contrast to Co-bearing N-doped carbon (CoNC), which lacks the Cu dopant, CuCo alloy nanoparticles (NPs) are contained by the Cu dopant within the carbonaceous matrix, giving CuCoNC more prominent electrochemical properties and larger porous structures and highly nitrogen moieties. CuCoNC, as a result, has a significantly higher capability compared to CoNC and Co3O4 NPs, for Oxone activation to degrade a toxic contaminant, Rhodamine B (RDMB). Furthermore, CuCoNC+Oxone has a smaller activation energy for RDMB elimination and maintains its superior effectiveness for removing RDMB in various water conditions. The computational chemistry insights have revealed the RDMB degradation mechanism. This study reveals that CuCoNC is a useful activator for Oxone to eliminate RDMB.

Magnetic Fe3O4 nanoparticles loaded guava leaves powder impregnated into calcium alginate hydrogel beads (Fe3O4-GLP@CAB) for efficient removal of methylene blue dye from aqueous environment: Synthesis, characterization, and its adsorption performance.

In the present work, a novel Fe3O4-GLP@CAB was successfully synthesized via a co-precipitation procedure and applied for the removal of methylene blue (MB) from aqueous environment. The structural and physicochemical characteristics of the as-prepared materials were explored using a variety of characterization methods, including pHPZC, XRD, VSM, FE-SEM/EDX, BJH/BET, and FTIR. The effects of several experimental factors on the uptake of MB using Fe3O4-GLP@CAB were examined through batch experiments. The highest MB dye removal efficiency of Fe3O4-GLP@CAB was obtained to be 95.2 % at pH 10.0. Adsorption equilibrium isotherm data at different temperatures showed an excellent agreement with the Langmuir model. The adsorption uptake of MB onto Fe3O4-GLP@CAB was determined as 136.7 mg/g at 298 K. The kinetic data were well-fitted by the pseudo-first-order model, indicating that physisorption mainly controlled it. Several thermodynamic variables derived from adsorption data, like as ΔGo, ΔSo, ΔHo, and Ea, accounted for a favourable, spontaneous, exothermic, and physisorption process. Without seeing a substantial decline in adsorptive performance, the Fe3O4-GLP@CAB was employed for five regeneration cycles. Because they can be readily separated from wastewater after treatment, the synthesized Fe3O4-GLP@CAB was thus regarded as a highly recyclable and effective adsorbent for MB dye.

Hollow-Structured N-doped carbon-embedded CoFe NanoAlloy for boosting activation of Monopersulfate: Engineered interface and heteroatom Doping-Induced enhancements.

While transition metals are useful for activating monopersulfate (MPS) to degrade contaminants, bimetallic alloys exhibit stronger catalytic activities owing to several favorable effects. Therefore, even though Co is an efficient metal for MPS activation, CoFe alloys are even more promising heterogeneous catalysts for MPS activation. Immobilization/embedment of CoFe alloy nanoparticles (NPs) onto hetero-atom-doped carbon matrices appears as a practical strategy for evenly dispersing CoFe NPs and enhancing catalytic activities via interfacial synergies between CoFe and carbon. Herein, N-doped carbon-embedded CoFe alloy (NCCF) is fabricated here to exhibit a unique hollow-engineered nanostructure and the composition of CoFe alloy by using Co-ZIF as a precursor after the facile etching and Fe doping. The Fe dopant embeds CoFe alloy NPs into the hollow-structured N-doped carbon substrate, enabling NCCF to possess the higher mesoscale porosity, active N species as well as more superior electrochemical properties than its analogue without Fe dopants, carbon matrix-supported cobalt (NCCo). Thus, NCCF exhibits a considerably larger activity than NCCo and the benchmark catalyst, Co3O4 NP, for MPS activation to degrade an environmental hormone, dihydroxydiphenyl ketone (DHPK). Besides, NCCF + MPS shows an even lower activation energy for DHPK degradation than literatures, and retains its high efficiency for eliminating DHPK in different water media. DHPK degradation pathway and ecotoxicity assessment are unraveled based on the insights from the computational chemistry, demonstrating that DHPK degradation by NCCF + MPS did not result in the formation of toxic and highly toxic by-products. These features make NCCF a promising heterogeneous catalyst for MPS activation to degrade DHPK.

Ultrafine cobalt nanoparticle-embedded leaf-like hollow N-doped carbon as an enhanced catalyst for activating monopersulfate to degrade phenol.

While cobalt (Co) stands out as the most effective non-precious metal for activating monopersulfate (MPS) to degrade organic pollutants, Co nanoparticles (NPs) are easily aggregated, losing their activities. As many efforts have attempted to immobilize Co NPs on supports/substrates to minimize the aggregation issue, recently hollow-structured carbon-based materials (HSCMs) have been regarded as promising supports owing to their distinct physical and chemical properties. Herein, in this study, a special HSCM is developed by using a special type of ZIF (i.e., ZIF-L) as a precursor. Through one-step chemical etching with tannic acid (TA), the resultant product still remains leaf-like morphology of pristine ZIF-L but the inner part of this product becomes hollow, which is subsequently transformed to ultrafine Co-NP embedded hollow-structured N-doped carbon (CoHNC) via pyrolysis. Interestingly, CoHNC exhibits superior catalytic activities than CoNC (without hollow structure) and the commercial Co3O4 NPs for activating MPS to degrade phenol. The Ea value of phenol degradation by CoHNC + MPS was determined as 44.3 kJ/mol. Besides, CoHNC is also capable of effectively activating MPS to degrade phenol over multiple-cycles without any significant changes of catalytic activities, indicating that CoHNC is a promising heterogeneous catalyst for activating MPS to degrade organic pollutants in water.

The use of eggshell membrane for the treatment of dye-containing wastewater: Batch, kinetics and reusability studies.

The worldwide consumption of eggs is very high, leading to about 250,000 tons of eggshell membrane (ESM) waste annually. The present research thus investigated the potential use of ESM as an inexpensive and abundant adsorbent for Reactive Red 120 (RR120) in aqueous solutions, a widespread hydrophilic azo dye used in the textile industry. The chemical structure and morphology of ESM were characterized using various spectroscopic methods, including scanning electron microscopy, Fourier transform infrared spectroscopy, and elemental analysis. It was found that natural ESM has a porous structure and surface functional groups that are suitable for the adsorption of the target molecules. The impact of the operating conditions, including the variation in the pH and temperature, on the RR120 sorption capacity and mechanisms of ESM was also analyzed. The maximum monolayer adsorption ability of ESM for RR120 was found to be 191.5 mg/g at 318 K, and the sorption process was spontaneous and endothermic. The adsorption of RR120 onto ESM was significantly influenced by the solution pH and the use of NaOH as eluent, indicating that the driving force for this adsorption was electrostatic attraction. Subsequent desorption experiments using 0.1 M NaOH resulted in satisfactory recovery efficiency. Kinetic, isothermic, and thermodynamic analysis was also conducted to support the experimental findings. The experimental results for the adsorption kinetics of ESM were fitted by a pseudo-second-order model. In conclusion, ESM has the potential to be utilized as an eco-friendly and cost-effective adsorbent for the removal of RR120 from aqueous solutions.

Coal bottom ash derived zeolite (SSZ-13) for the sorption of synthetic anion Alizarin Red S (ARS) dye.

SSZ-13 zeolite was successfully synthesized from coal bottom ash (CBA) upon hydrothermal treatment for selective sorption of Alizarin Red S (ARS) dye. The characterization of CBA, and SSZ-13 were performed using BET, SEM, FTIR, XRF, and XRD techniques. The optimal fusion ratio (CBA: NaOH) was identified as 1:3, resulting zeolite SSZ-13 with a specific surface area of 206.6 m2/g, compared to raw CBA (7.81 m2/g). The kinetics, isotherms, and thermodynamics of the ARS adsorption onto the SSZ-13, and CBA were assessed under various conditions. The results indicated that the adsorption phenomenon is optimal under acidic medium (pH = 2 for CBA, pH = 3 for SSZ-13); at ambient room temperature of 298 K; adsorbent dosage of 0.03 g, contact time of 120 min. Further, the equilibrium data fitted well to Langmuir isotherm (qe = 210.75 mg/g), following pseudo-second-order kinetics. Moreover, the chemisorption phenomenon is clearly described using Elovich kinetic model. Various thermodynamic parameters signifies the adsorption phenomenon is spontaneous, and endothermic in nature. Finally, regeneration studies revealed the sensitivity of SSZ-13 zeolite towards 0.1 M NaOH/EtOH eluent in recovery and the possibility of reuse to five successive adsorption/desorption cycles. Thus, hydrothermal treatment of CBA has potential in producing zeolites suitable to adsorption.

Removal of Pb(II) ions by using magnetic chitosan-4-((pyridin-2-ylimino)methyl)benzaldehyde Schiff's base.

A novel crosslinked magnetic chitosan-4-((pyridin-2-ylimino)methyl)benzaldehyde Schiff's Base (m-CSPIB) was prepared by crosslinking of magnetic iron oxide nanoparticles with chitosan-4-((pyridin-2-ylimino)methyl)benzaldehyde schiff's base and used as an biosorbent for the removal of Pb(II) ions from aqueous environment. The biopolymer has been characterized by XRD, FT-IR, SEM, TEM, 1H NMR and VSM analysis. Kinetic studies were performed, and the data were fitted well with the pseudo-second-order model. The equilibrium data followed Langmuir isotherm model and the maximum monolayer sorption capacity was found to be 104.16 for Pb(II) ions at 323K. Different thermodynamic parameters namely, change in Gibbs free energy, enthalpy change, and entropy changes were also evaluated from the temperature dependence, and the results suggested that the sorption of Pb(II) onto m-CSPIB was feasible, spontaneous and endothermic in nature.