Investigation of adsorption and biosorption features of bio-functionalized poly(GMA-Co-EGDMA) polymer beads in the treatment of nicotine from tobacco industry.

The investigation of multifunctional materials for modern enzyme immobilization is an attractive subject in advanced adsorption and biosorption applications. In the present study, the feasibility of immobilization of Lipozyme TL 100L (LPZM) on 3-aminopropyltriethoxysilane (APTES) modified poly-(GMA-co-EGDMA) (PEGDMA) was investigated for adsorption and biosorption of nicotine from aqueous solution. Characterization tests confirmed successful immobilization of lipozyme which significantly altered thermal behavior, surface characteristics, and surface morphology of PEGDMA and PEGDMA/APTES. In addition, the immobilization yields were calculated as 85.0% and 72.0% onto PEGDMA/APTES using physical adsorption and covalent immobilization methods, respectively. The nicotine removal efficiencies were calculated to be 66.4%, 79.0%, 98.9%, and 85.7%, using raw PEGDMA, PEGDMA/APTES, PEGDMA/APTES@LPZM, and PEGDMA/APTES/GU@LPZM, respectively. For the raw PEGDMA, the Langmuir isotherm was best fitted to the adsorption data, while Langmuir-Freundich model described well the adsorption process on PEGDMA/APTES and PEGDMA/APTES@LPZM. The maximum adsorption capacities of Langmuir-Freundlich model increased from 8.118 to 17.32 mg/g after enzyme immobilization. The negative enthalpy value, ΔH° (- 10.37 kJ/mol), revealed that the nicotine adsorption on PEGDMA/APTES@LPZM was exothermic in nature, which was corroborated by the decrease observed in the number of adsorbed molecules with increasing temperature. In the kinetic experiments, the adsorption on PEGDMA and PEGDMA/APTES@LPZM reached equilibrium with the removal percentages as 66.4% and 98.9% at the end of 3 h, respectively. The nicotine adsorption performances in real water matrices were also investigated, and PEGDMA/APTES@LPZM showed satisfactory reusability with removal percentage decreased from 98.9% (1st cycle) to 83.0% (6th cycle).

Deposition of CaFe2O4 and LaFeO3 perovskites on polyurethane filter: A new photocatalytic support for flowthrough degradation of tetracycline antibiotic.

The immobilization of powder catalysts on substrates has been the subject of increasing interest in the field of photocatalysis. For the first time, highly efficient LaFeO3 and CaFe2O4 perovskites were hydrothermally deposited on polyurethane filters (LFO/PU, CFO/PU). Furthermore, the photo-Fenton catalytic decomposition of tetracycline antibiotic by the new catalyst filters was explored under visible light irradiation. The structural, optical, and morphological characteristics of the photo-active filters were investigated using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM-EDS), X-ray diffraction (XRD), UV-visible diffusion spectra (UV-vis DRS), X-Ray fluorescence (XRF), and thermogravimetric/dynamic thermal analyses (TG-DTG). The decomposition studies were conducted in both batch and micro-flow reactor systems. The effects of solution pH, reactive species, and water type on the reaction mechanism were examined. It was found that the photo-Fenton degradation of tetracycline improved when the perovskite proportions on the filter were increased; the removal rates reached 94% and 80% forLFO/PU and CFO/PU, respectively. The high degradation performance obtained in lake (∼71%) and seawater (∼76%) demonstrated the great potential of photo-active catalyst filters, and their excellent stability was confirmed by reusability tests. In the continuous flow system, the photocatalytic filters kept the degradation rate stable at 83% and 44% after 7 h of examination forLFO/PU and CFO/PU, respectively. These results suggest that the as-prepared catalytic filters may be suitable for industrial photocatalytic applications.

Construction of novel Zn2TiO4/g-C3N4 Heterojunction with efficient photodegradation performance of tetracycline under visible light irradiation.

This work presented facile fabrication of carbon nitride (CN)/zinc titanate (ZT) heterojunction by one-step ball milling process for visible light-induced photocatalytic degradation. The phase structures, morphologies, functional groups, and optical properties of the prepared materials were systematically characterized by XRD, FTIR, UV-Vis DRS, and SEM techniques. The ball milling for 10 min significantly improved visible light absorption properties; the as-synthesized ZT/CN catalyst (2.8 eV) showed lower band gap energy than bare ZT (3.2 eV). This result revealed a successful incorporation. The photocatalytic activities of the heterostructure catalysts (ZT/CN) evaluated by degrading tetracycline under visible light irradiation and highest TC removal rate were obtained as 0.0193 min-1 for ZT/CN/5, which was 6.2 times higher than that of bare CN. The most efficient photocatalyst (ZT/CN/5) could be performed three times without any loss of phase. In addition, the heterostructure catalyst was found as promising candidate for efficient photocatalytic degradation of other antibiotics and dye components.

Fabrication of Zr-doped TiO2/chitosan composite catalysts with enhanced visible-light-mediated photoactivity for the degradation of Orange II dye.

Zirconium/titanium/chitosan (Zr/Ti/CHT) composite catalysts were synthesized by sol-gel method using different chitosan amounts (5-20 wt.%) and their activity in the photocatalytic degradation of Orange II dye was evaluated for the first time. The results were compared with Zr/Ti, Zr/CHT and Ti/CHT catalysts. The composite catalysts were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray photoelectron spectroscopy analysis. XRD analysis revealed that the Zr/Ti/CHT composite catalyst showed high crystallinity of anatase TiO2 phase. Photocatalytic experiments showed that adding CHT into the catalyst structure increased the photocatalytic degradation under visible light irradiation. Also, the first-order reaction rate constant, kapp, was calculated using the Langmuir-Hinshelwood (L-H) equation. The kapp values were found to be 0.009, 0.0013, 0.012 and 0.014 min-1 for Zr/Ti, Zr/CHT, Ti/CHT and Zr/Ti/CHT, respectively. According to stability tests, after the first cycle Orange II dye degradation was found to be 95%, while it was 37% after the fifth cycle. The results showed that the composite catalyst could be used several times for Orange II dye degradation.