Deepak Pathania

Adsorptional photocatalytic degradation of methylene blue onto pectin-CuS nanocomposite under solar light.

This study describes the effect of adsorption on methylene blue degradation using pectin-CuS nanocomposite (PCSNC). The nanocomposite was synthesized using co-precipitation methods followed by direct encapsulation with pectin. The synthesized nanocomposite was characterized by SEM, TEM, XRD, FTIR and UV-vis spectral technique. The adsorption and photocatalytic efficiencies of PCSNC were compared with copper sulphide nanoparticle (CSNP). The dye removal was studied under different reaction conditions. The adsorption capacity of pectin based nanocomposite was higher due to other free functional group on pectin surface after connecting to nanoparticles. The simultaneous adsorption and photodegradation process (A+P) was the most efficient process due to rapid destruction of adsorbed dye molecules. The complete COD removal was attained in 10h using PCSNC/A+P process. On comparing with CSNP, pectin-CuS nano composite showed more degradation efficiency and reusability for MB degradation.

Preparation of bio-based porous carbon by microwave assisted phosphoric acid activation and its use for adsorption of Cr(VI)

Ficus carica fiber based activated carbon (FCAC) was used as a potential adsorbent for Cr(VI) removal from aqueous system. The adsorbent was prepared by carbonization of F. carica fiber followed by H3PO4 activation under microwave radiations. The activated carbon was characterized using scanning electron microscopy and Fourier transformer infrared spectroscopy. The adsorption data were well studied for adsorption isotherms, kinetics models, and thermodynamics. Adsorption of chromium ion followed the second-order kinetics and best fitted the Langmuir adsorption isotherms. The maximum adsorption capacity of Cr(VI) onto FCAC was 44.84 mg/g. The calculated values of thermodynamic parameters like enthalpy change (ΔH°), entropy change (ΔS°), and free energy change (ΔG°) were found to be 7.85 kJ/mol, 69.17 J/mol K, and -13.11 kJ/mol, respectively. Adsorption process was spontaneous and endothermic in nature.

Magnetically recoverable ZrO2/Fe3O4/chitosan nanomaterials for enhanced sunlight driven photoreduction of carcinogenic Cr(VI) and dechlorination & mineralization of 4-chlorophenol from simulated waste water

In this laboratory-scale experiment we report the treatment of carcinogenic Cr(VI) and 4-chlorophenol by ferromagnetic ZrO2/Fe3O4 nano-heterojunctions supported on chitosan. A combination of different semiconductors with different photo-activities has proven to be a tested and effective technique for harnessing solar light in waste water treatment. The prepared heterojunction and its composite with chitosan has been characterized by X-Ray Diffraction (XRD), Fourier Transform Infra Red spectroscopy (FTIR), High Resolution Transmission Electron Microscopy (HRTEM), Small Area Electron Diffraction (SAED), Vibrating Sample Magnetometry (VSM), Energy Dispersive X-ray analysis (EDX), UV-visible spectrophotometry and Brunauer–Emmet–Teller surface area analysis (BET). Treatment of chlorophenols is challenging because of their hydrophobicity and stability. In our study we have reported excellent results for the dechlorination of 4-chlorophenol and the results were analyzed in terms of Liquid Chromatography-Mass Spectrometry (LC-MS), Chemical Oxygen Demand analysis (COD) and emission. 88.6% of 4-CP degradation was achieved in the presence of ZrO2/Fe3O4/chitosan in 3 h under sunlight and a reduction of 90.2% for Cr(VI) was obtained. The heterojunction formation leads to charge separation and decreased recombination of charge carriers. The synergistic effects of charge separation in the heterojunction, alcohols, peroxide, magnetism and adsorption with essential explanation of mechanisms make this study important and promising.

Acrylic acid grafted cellulosic Luffa cylindrical fiber for the removal of dye and metal ions.

Acrylic acid grafted cellulosic Luffa cylindrical fiber was utilized for the removal of methylene blue and metal ions from the water system using batch process. The grafted sample used was found to demonstrate a maximum grafting efficiency of 90.8% under concentrations of 0.432×10(-3) mol/L, temperature of 35 °C, time of 60 min and pH of 7.0 respectively. The remarkable improvement in thermal properties of the grafted sample was observed. The formation of new bands in FTIR spectra of grafted sample confirmed the grafting of acrylic acid onto the cellulosic fiber. The maximum adsorption capacity of dye onto adsorbent was observed to be 62.15 mg g(-1) at 175 min. A maximum removal of 45.8% was observed for Mg(2+) as compared to other metal ions. High values of correlation coefficient for methylene blue (0.995) and metal ions such as Mg(2+) (0.996), Ni(2+) (0.995), Zn(2+) (0.996) confirmed the applicability of Langmuir isotherm that assumed a monolayer coverage and uniform activity distribution on the adsorbent surface.

Modification of Hibiscus cannabinus fiber by graft copolymerization: application for dye removal

AbstractHibiscus cannabinus fiber was modified by graft copolymerization with vinyl monomer acrylic acid (AAc) and binary mixture of AAc and acrylamide (AAm). The different reaction parameters were optimized to get maximum grafting yield. The optimized percent grafting for AAc and binary mixture (AAc + AAm) was found to be 93.6 and 74.6%, respectively, at the molar concentration of 0.35 M for AAc and 0.4 M for AAm. The raw AAc grafted H. cannabinus fiber (Hcf-g-polyAAc) and AAc + AAm grafted H. cannabinus fiber (Hcf-g-polyAAc + AAm) were characterized by FTIR and scanning electron microscopy. The modified H. cannabinus fibers were used as potential candidate for the removal of dye from aqueous system.

Revolution from monometallic to trimetallic nanoparticle composites, various synthesis methods and their applications: A review

Trimetallic nanoparticles are mainly formed by the combination of three different metals. The trimetallic catalysts were considerably more professional than bimetallic one. The trimetallic and bimetallic nanoparticles are of enormous attention than that of monometallic in both technological and scientific view as in these nanoparticles the catalytic properties can be tailored better than that of in the single monometallic catalyst. The trimetallic nanoparticles have been synthesized by different methods such as microwave, selective catalytic reduction, micro-emulsion, co-precipitation and hydrothermal etc. The surfaces area of trimetallic nanoparticles is comparatively unstable and thus gets simply precipitated away from their solution and ultimately resulted in their reduced catalytic activity. By using stabilizers like block copolymers, organic ligands, surfactants and dendrimers the trimetallic nanoparticles can be stabilized. The nanocomposites of trimetallics have been synthesized with inorganic and organic compounds such as: carbon, graphene, gelatin, cellulose, starch, chitosan, alginate, collagen and Al2O3 etc. Trimetallic nanoparticles are used as a catalyst due to their outstanding electrochemical catalytic activity in comparison with the monometallic or bimetallic nanoparticles.

Use of pectin-thorium (IV) tungstomolybdate nanocomposite for photocatalytic degradation of methylene blue

Pectin-thorium (IV) tungstomolybdate (Pc/TWM) nanocomposite was prepared by mixing biopolymer pectin with its inorganic counterpart thorium (IV) tungstomolybdate (TWM) using the sol-gel method. The nanocomposite was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). Distribution coefficient, thermal stability, pH titrations, elution and concentration behaviour were investigated to explore the ion exchange behaviour of nanocomposite material. Pc/TWM exhibited higher ion exchange capacity (1.10 mequiv/g) than its inorganic counterpart (0.62 mequiv/g). The Pc/TWM nanocomposite ion exchanger was thermally stable as it retained 59% of its ion exchange capacity upto 400°C. The pH titrations study revealed the bifunctional nature of Pc/TWM. In order to explore the environmental applicability of the Pc/TWM nanocomposite material, its antibacterial and photocatalytic activities was investigated. 76% of methylene blue dye was photocatalytically degraded after five hours exposure. It also totally inhibited Escherichia coli at 400 μg/ml concentration of Pc/TWM nanocomposite.

Novel guar gum/Al2O3 nanocomposite as an effective photocatalyst for the degradation of malachite green dye.

Guar gum/Al2O3 (GG/AO) nanocomposite was prepared using simple and cost effective sol-gel method. This nanocomposite was characterized by several analytical techniques viz. scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermal analysis (TGA/DTA), Fourier transform infrared spectroscopy (FTIR) and ultraviolet-visible spectroscopy (UV-vis). The FTIR analysis confirmed that GG/AO composite material was formed. TEM images inferred the particle size in the range between 20 and 45nm. GG/AO nanocomposite exhibited good photocatalytic performance for malachite green (MG) dye (dye initial concentration 1.5×10(-5)M) degradation from aqueous phase. The adsorption followed by photocatalysis and coupled adsorption/photocatalysis reaction achieved about 80% and 90% degradation of MG dye under solar irradiation. Antibacterial test showed the excellent activity of GG/AO nanocomposite against Staphylococcus aureus.

Biodegradable and conducting hydrogels based on Guar gum polysaccharide for antibacterial and dye removal applications

Conducting hydrogels possessing antibacterial activity were developed using a two-step free-radical aqueous polymerization method to incorporate polyaniline chains into an adsorbent Guar gum/acrylic acid hydrogel network. The material properties of the synthesized samples were characterized using FTIR spectroscopy, thermal analysis and scanning electron microscopy techniques. Conducting hydrogels were tested for antibacterial activities against gram-positive Staphylococcus aureus and gram-negative Escherichia coli bacteria and demonstrated antibacterial activity. Synthesized hydrogel samples can be potential adsorbent materials for dye removal applications.

Adsorptional removal of methylene blue by guar gum-cerium (IV) tungstate hybrid cationic exchanger.

Guar gum-cerium (IV) tungstate nanocomposite (GG/CTNC) cationic exchanger was synthesized using simple sol gel method. The GG/CTNC was characterized using X-ray diffraction (XRD), Fourier transmission infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive X-ray spectrophotometer (EDX). The XRD studies confirmed amorphous and fibrous in nature of GG/CTNC. The high percentage of oxygen in the nanocomposite material confirmed the functionality tungstate (WO4(-)). The ion exchange capacity of GG/CTNC for Na(+) ion was observed to be 1.30 mequivg(-1). The hybrid exchanger was used as potential adsorbent for the removal of methylene blue (MB) from aqueous system. The correlation coefficients value indicated a good fit of monolayer Langmuir model to the adsorption of methylene blue onto GG/CTNC. The adsorption kinetic study revealed that the adsorption process followed the pseudo second order kinetic. The Gibbs free energy (ΔG) values confirmed the spontaneous nature of adsorption process.