Synthesis and characterization of Cu(OH)2-NWs-PVA-AC Nano-composite and its use as an efficient adsorbent for removal of methylene blue

The present study focused on the synthesis of copper hydroxide nanowires decorated on activated carbon (Cu(OH)2-NWs-PVA-AC). The obtained Cu(OH)2-NWs-PVA-AC Nano-composite was distinguished by XRD, SEM, EDX, BET, FTIR and XPS respectively. Besides, different variables such as solution pH, and initial dye concentration, contact time, and temperature were performed on the adsorption efficiency of MB in a small batch reactor. Further, the experimental results are analyzed by various kinetic models via PFO, PSO, intra-particle diffusion and Elovich models, and the results revealed that among the kinetic models, PSO shows more suitability. In addition, different adsorption isotherms were applied to the obtained experimental data and found that Langmuir–Freundlich and Langmuir isotherm were best fits with the maximum adsorption capacity of 139.9 and 107.6 mg/g, respectively. The Nano-composite has outstanding MB removal efficiency of 94–98.5% with a span of 10 min. and decent adsorption of about 98.5% at a pH of 10. Thermodynamic constants like Gibbs free energy, entropy, and enthalpy were analyzed from the temperature reliance. The results reveal the adsorption processes are spontaneous and exothermic in nature. The high negative value of ?G° (- 44.11 to - 48.86 kJ/mol) and a low negative value of ?H° (- 28.96 kJ/mol) show the feasibility and exothermic nature of the adsorption process. The synthesized dye was found to be an efficient adsorbent for the potential removal of cationic dye (methylene blue) from wastewater within a short time

A critical assessment of technical advances in pharmaceutical removal from wastewater – A critical review

Use of pharmaceutical products has seen a tremendous increase in the recent decades. It has been observed that more than thirty million tons of pharmaceuticals are consumed worldwide. The used pharmaceutical products are not completely metabolized in human and animal body. Therefore, they are excreted to the environment and remain there as persistent organic chemicals. These compounds emerge as toxic contaminants in water and affect the human metabolism directly or indirectly. This literature review is an endeavour to understand the origin, applications and current advancement in the removal of pharmaceuticals from the environment. It discusses about the pharmaceuticals used in medical applications such diagnosis and disease treatment. In addition, it discusses about the recent approaches applied in pharmaceutical removal including microbial fuel cells, biofiltration, and bio nanotechnology approaches. Moreover, the challenges associated with pharmaceutical removal are presented considering biological and environmental factors. The review suggest the potential recommendations on pharmaceutical removal.The corresponding author Prof. Vinay Kumar is thankful to all the co-authors for their collaborative efforts in writing this paper. This work was supported by Department of Community Medicine, Saveetha Medical College and Hospital, Saveetha Institute of Medical and Technical Sciences (SIMATS), Chennai, India.Peer reviewe

Mechanical Properties and Degradation Rate of Poly(Sorbitol Adipate-Co-Dioladipate) Copolymers Obtained with a Catalyst-Free Melt Polycondensation Method

A new family of polyester-based copolymers—poly(sorbitol adipate-co-ethylene glycol adipate) (PSAEG), poly(sorbitol adipate-co-1,4 butane diol adipate) (PSABD), and poly (sorbitol adipate-co-1,6 hexane diol adipate) (PSAHD)—was obtained with a catalyst-free melt polycondensation procedure using the multifunctional non-toxic monomer sorbitol, adipic acid, and diol, which are acceptable to the human metabolism. Synthesized polyesters were characterized by FTIR and 1H NMR spectroscopy. The molecular weight and thermal properties of the polymers were determined by MALDI mass spectroscopy, differential scanning calorimetry (DSC), and thermogravimetric analysis. The degradation rate was investigated, at 37 °C, in 0.1M NaOH (pH 13) and in phosphate-buffered solution (PBS) at pH 7.4. It was found that the polymers degraded faster in NaOH (i.e., in a day) compared to their degradation in PBS, which was much slower (in a week). The highest degradation rate was noticed for the PSAEG sample in both media, whereas PSAHD was the most stable polymer at pH 7.4 and 13. A reduced hydrophilicity of the polymers with diol length was indicated by low swelling percentage and sol content in water and DMSO. Mechanical studies prove that all the polymers are elastomers whose flexibility increases with diol length, shown by the increase in percentage of elongation at break and the decrease in tensile stress and Young’s modulus. These biodegradable copolymers with adaptable physicochemical characteristics might be useful for a broad variety of biological applications by merely varying the length of the diol

Synthesis of copper oxide nanowires-activated carbon (AC@CuO-NWs) and applied for removal methylene blue from aqueous solution: kinetics, isotherms, and thermodynamics

In the present study, we focused on the synthesis of copper oxide nanowires decorated on activated carbon (AC@CuO-NWs) for the removal of methylene blue (MB) from aqueous solutions. The AC@CuO-NWs nanocomposite is synthesized via simple precipitation method and characterized by using various techniques which includes scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX), and X-rays diffraction analysis (XRD). XRD results confirmed the monoclinic structure of CuO-NWs with the average crystalline size ~ 17.48 nm. The SEM images indicated the wire-like structure and EDX analysis confirms the CuO nanomaterial. The SEM image shows that nanowires are agglomerated to form like flower shape. The batch adsorption experiments were optimized using various parameters such as pH, contact time, initial dye concentration, kinetic and isotherm studies. The results showed that the adsorption processes were well fitted with the PSO model. The adsorption equilibrium experimental data fitted to the Langmuir models with a maximum adsorption capacity of 141.73 mg/g at 328 K. The thermodynamics results reveal that the adsorption processes are spontaneous and endothermic in nature. The high negative value of ΔG° and a low value of ΔH° show the feasibility with physisorption and endothermic nature of the adsorption process. The acquire results indicating that AC@CuO-NWs based nanocomposite is having the high MB adsorption capacity in short equilibrium period and good substitute as the low-cost adsorbent in wastewater treatment. The synthesis of AC@CuO-NWs nanocomposite material is simple, easy and scale-up that might be efficiently used in water treatment technologies

Fabrication of Eco-Friendly Polyelectrolyte Membranes Based on Sulfonate Grafted Sodium Alginate for Drug Delivery, Toxic Metal Ion Removal and Fuel Cell Applications

Polyelectrolyte membranes (PEMs) are a novel type of material that is in high demand in health, energy and environmental sectors. If environmentally benign materials are created with biodegradable ones, PEMs can evolve into practical technology. In this work, we have fabricated environmentally safe and economic PEMs based on sulfonate grafted sodium alginate (SA) and poly(vinyl alcohol) (PVA). In the first step, 2-acrylamido-2-methyl-1-propanesulphonic acid (AMPS) and sodium 4-vinylbenzene sulfonate (SVBS) are grafted on to SA by utilizing the simple free radical polymerization technique. Graft copolymers (SA-g-AMPS and SA-g-SVBS) were characterized by 1H NMR, FTIR, XRD and DSC. In the second step, sulfonated SA was successfully blended with PVA to fabricate PEMs for the in vitro controlled release of 5-fluorouracil (anti-cancer drug) at pH 1.2 and 7.4 and to remove copper (II) ions from aqueous media. Moreover, phosphomolybdic acids (PMAs) incorporated with composite PEMs were developed to evaluate fuel cell characteristics, i.e., ion exchange capacity, oxidative stability, proton conductivity and methanol permeability. Fabricated PEMs are characterized by the FTIR, ATR-FTIR, XRD, SEM and EDAX. PMA was incorporated. PEMs demonstrated maximum encapsulation efficiency of 5FU, i.e., 78 ± 2.3%, and released the drug maximum in pH 7.4 buffer. The maximum Cu(II) removal was observed at 188.91 and 181.22 mg.g–1. PMA incorporated with PEMs exhibited significant proton conductivity (59.23 and 45.66 mS/cm) and low methanol permeability (2.19 and 2.04 × 10−6 cm2/s)

Photocatalytic and antimicrobial properties of microwave synthesized mixed metal oxide nanocomposite

CdO-CuO-ZnO nanocomposite (CCZ NC) was prepared by a simplistic microwave-assisted route and inspected by utilizing diverse spectroscopic ways. The structural and morphological properties of CCZ NC were investigated via XRD, FTIR, and SEM with EDAX analysis. The XRD pattern reveals the crystal structure of cubic CdO, monoclinic CuO, and hexagonal ZnO with average crystallite size around 39 (CdO), 28 (CuO), 30 (ZnO) nm. The FTIR spectrum exposed distinctive vibration frequencies at 566, 630, and 451 cm?1 allocated to Cu-O, Cd-O, and Zn-O stretching vibrations, correspondingly. The flower-like structure was validated with SEM with EDAX investigation. The optical properties of CCZ NC were deliberated via UV?Visible and fluorescence spectroscopy. The optical bandgap of the synthesized CCZ NC is 2.8 eV. High-performance alizarin red S dye photocatalytic degradation (93% at 120 mins) was observed on the flower-like structure CCZ NC, under natural sunlight irradiation. Besides, the antibacterial activities of CCZ NC were investigated against foodborne microorganisms. CCZ NC showed a good zone of inhibition against Staphylococcus aureus (28 mm) and Salmonella typhi (22 mm). These results indicate that synergistic CCZ NC is a promising material for the functioning of bio-imaging, water purifying process, and pharmaceutical applications.Scopu

Fabrication of Polyelectrolyte Membranes of Pectin Graft-Copolymers with PVA and Their Composites with Phosphomolybdic Acid for Drug Delivery, Toxic Metal Ion Removal, and Fuel Cell Applications

In this study, a simple method for the fabrication of highly diffusive, adsorptive and conductive eco-friendly polyelectrolyte membranes (PEMs) with sulfonate functionalized pectin and poly(vinyl alcohol)(PVA) was established. The graft-copolymers were synthesized by employing the use of potassium persulfate as a free radical initiator from pectin (PC), a carbohydrate polymer with 2-acrylamido-2-methyl-1-propanesulphonic acid (AMPS) and sodium 4-vinylbenzene sulphonate (SVBS). The PEMs were fabricated from the blends of pectin graft-copolymers (PC-g-AMPS and PC-g-SVBS) and PVA by using a solution casting method, followed by chemical crosslinking with glutaraldehyde. The composite PEMs were fabricated by mixing phosphomolybdic acid with the aforementioned blends. The PEMs were successfully characterized by FTIR, XRD, SEM, and EDAX studies. They were assessed for the controlled release of an anti-cancer drug (5-fluorouracil) and the removal of toxic metal ions (Cu2+) from aqueous media. Furthermore, the composite PEMs were evaluated for fuel cell application. The 5-fluorouracil release capacity of the PEMs was found to be 93% and 99.1% at 300 min in a phosphate buffer solution (pH = 7.4). The highest Cu2+ removal was observed at 206.7 and 190.1 mg/g. The phosphomolybdic acid-embedded PEMs showed superior methanol permeability, i.e., 6.83 × 10−5, and 5.94 × 10−5, compared to the pristine PEMs. Furthermore, the same trend was observed for the proton conductivities, i.e., 13.77 × 10−3, and 18.6 × 10−3 S/cm at 30 °C

Metal-Doped Graphitic Carbon Nitride Nanomaterials for Photocatalytic Environmental Applications—A Review

In the current world situation, population and industrial growth have become major problems for energy and environmental concerns. Extremely noxious pollutants such as heavy metal ions, dyes, antibiotics, phenols, and pesticides in water are the main causes behind deprived water quality leading to inadequate access to clean water. In this connection, graphite carbon nitride (GCN or g-C3N4) a nonmetallic polymeric material has been utilized extensively as a visible-light-responsive photocatalyst for a variety of environmental applications. This review focuses on recent developments in the design and photocatalytic applications of metal-doped GCN-based nanomaterials in CO2 photoreduction, water splitting toward hydrogen production, bacterial disinfection, and organic pollutant degradation. Additionally, this review discusses various methods of using GCN-based materials to optimize dye sensitization, metal deposition, ion doping, and their environmental applications

Indonesian kaolin supported nZVI (IK-nZVI) used for the an efficient removal of Pb(II) from aqueous solutions: kinetics, thermodynamics and mechanism

A remarkably efficient Indonesian Kaolin (IK) supported nano zerovalent iron composite (IK-nZVI) has been synthesized, and subjected to the elimination Pb(II) from the wastewater. The results were authenticate the nZVI nanoparticles have a chain shape and establish as separable nanospheres with an average size (29.95 nm) on the surface of IK. The FTIR spectra demonstrate the presence of Al-O as well as Si-O bonds. XRD results demonstrate the presence of zerovalent iron. SEM confirmed less agglomeration of Fe(0) nanoparticles which improves the mechanical strength. The weak signals of Fe and O confirm the establishment of zerovalent iron in nanocomposite. TEM demonstrates that the nanocomposite has a chain like structure. Pb(II)percentage removal was improved by rise in the IK-nZVI amount which results in rising the adsorption site. The nanocomposite had on optimum Pb(II) sorption at pH range of 4.5–6.5. The amount adsorbent increasing with the Pb(II) removal percentage was decreased. Kinetics study demonstrated that Pb(II) sorption was accomplished through more than one processes. IK was proved active support to progress the dispersion, and steadiness of IK-nZVI nanocomposite. The sorption processes pollutant was estimated through the kinetics models, and different sorption isotherm equations like Langmuir (LM), Langmuir-Freundlich (L-F), and Freundlich (FL) isotherms. The IK-nZVI typically accompanies outstanding Pb(II) removal efficiency of 98% and 96.05% with a span of 5 and 10 min for low and high concentrations, respectively. Significantly, the results reveal the maximum adsorption capability of the IK-nZVI is 192.0 mg/g. The thermodynamic study shown endothermic and spontaneous adsorption onto the IK-nZVI surface. Specifically, the IK-nZVI nanocomposite possesses key advantages in terms of simple method, nature friendly, cost-effectiveness, and decent adsorption efficiency for the potential elimination of toxic metal ion (Pb(II)) in the aqueous phase