Influences of Magnesium <Emphasis Type="Italic">tri-</Emphasis>Silicate on the Physical,Mechanical, and Degradable Properties of Ultraviolet (UV) Radiation Cured Plain Board Surface

A series of formulations were prepared with different percentages of oligomer, epoxy diacrylate (EA-1020 ), monomer, 1,6 Hexane diol diacrylate,(HDDA) and different percentages of filler (Magnesium tri-silicate, Mg₂Si₃O₈). Irgacure 369 [2-Benzyl-2-dimethyl-amine-1 (4-morpholinophenyl) butanone-1] was used in the formulations as photoinitiator. Ultraviolet (UV) cured thin polymer films were prepared from these formulating solutions on clean glass plates. Pendulum hardness (PH), gel content and macro scratch hardness (MSH) of the UV cured films were studied. One percent Mg₂Si₃O₈ containing formulation showed the premium properties. The substrates (plain board) were coated by these formulating solutions and cured under the same UV lamp at different intensities of radiation. Various properties of the coated surface such as PH, gloss, adhesion, abrasion and MSH were investigated. The base coat containing 1% Mg₂Si₃O₈ and top coat containing 48% HDDA produced the best performance among all the formulations inspected. The degradable properties in different weathering conditions on PH, gloss, adhesion, abrasion and MSH were measured. The surface cured with the optimized formulation (E) again yielded the minimum loss of the properties.     

防腐漆涂装含锌废水中锌粉的回收与利用

从水性环氧富锌涂料工业涂装废水中回收废锌粉,通过加热二甲基亚砜来溶解包覆于废锌粉表面的环氧树脂漆膜,得到回收锌粉,并将其再利用制防腐漆。在沉降时间12 h、热处理温度110 ℃、热处理时间60 min的条件下,废锌粉表面上的环氧树脂被去除,可直接以金属锌粉的形态加以回收利用,回收锌粉达到GB/T 6890—2012《锌粉》中的二级标准。使用后的溶剂经旋转蒸发后可再次使用,对锌粉的回收效果无影响。回收锌粉制备的防腐漆,其防腐蚀性能良好,可比市售锌粉。     

Distributed inner states TiO2-coated plastic fibers as photocatalysts for decomposing organic pollutants in water

A new method for decomposing organic pollutants in water is proposed. First, we used less pure titanium dioxide (TiO₂) particles as a photocatalyst material to achieve an absorption band that would be as wide as the spectrum for visible sunlight. The TiO₂ particles were coated onto the surface of transparent plastic fibers and used to decompose test solutions of rhodamine that were placed in open sunlight for several days. We observed an effective decomposition, and after completing the decomposition process, the fibers could be removed easily from the cleaned water leaving no TiO₂ in the water. Because there was no significant change in the elemental composition of the fiber surface after being used for cleaning the water, the coated fiber can be used repeatedly.     

Groundwater treatment and aquatic toxicity reduction at a chemical production site

Contaminated groundwater at a chemical antioxidant and phenolic resin chemical production site was subjected to treatability studies to develop design criteria for surface water discharge. Raw groundwater required pretreatment for total suspended solids (TSS) and color removal prior to treatment by ultraviolet light/hydrogen peroxide (UV/H₂O₂). Because of high capital and operating costs for UV/H₂O₂, biological treatment was evaluated as an alternate. Respirometric analyses showed that completely mixed activated sludge could be applied as a treatment technology to the groundwater. Biotreatment resulted in an approximately 70 percent reduction in soluble chemical oxygen demand (SCOD). Residual SCOD was recalcitrant to further biodegradation. The treated effluent was tested for aquatic toxicity using fathead minnows (Pimephales promelas) and Ceriodaphnia dubia and was found to be toxic. Toxicity reduction of biotreatment effluent was evaluated in bench-scale experiments using activated carbon adsorption, filtration, and UV/H₂O₂. Subsequent toxicity testing showed that filtration alone could reduce the bioeffluent toxicity and that residual SCOD was not the primary source of toxicity.     

The Role of Catalyst Properties on Methanol Oxidation over V2O5–TiO2 Using Ozone

Oxidation of methanol over V₂O₅ catalysts supported on anatase TiO₂ that were prepared using sol-gel formation and impregnation procedures were investigated. The effects of incorporating Mg in sol-gel to influence the properties of the catalyst were also studied. The process provides an alternative low temperature reaction pathway for reducing emissions of hazardous air pollutant (HAPs) such as methanol and total reduced sulfur compounds (TRS) from pulp and paper mills. The bulk and surface composition of the catalysts were determined by XRD and SEM-EDAX, respectively. The X-ray diffraction patterns of the vanadia–titania catalysts showed mainly the anatase phase of TiO₂. Temperature programmed desorption of methanol from the different catalyst showed that the α and β peaks differ significantly with V content and addition of Mg. The combination of gas phase and surface reactions on the V/TiO₂ catalysts reduced the amount of ozone required for high degradation of methanol to mainly CO _x with small quantities of methyl formate. In the absence of ozone the catalysts showed very low activity. It is hypothesized that the ozone is directly influencing the V⁴⁺ and V⁵⁺ redox cycle of the catalyst. Oxidation of methanol is influenced by the operation variables and catalyst properties. The results of this study revealed that the V content has significant influence on the catalyst activity, and the optimum vanadia loading of about 6 wt%. Higher turnover frequencies were observed over sol-gel catalysts than with catalysts prepared by the impregnation method.     

Photocatalytic Degradation of Poly(Vinyl Alcohol) on Pt/TiO<Subscript>2</Subscript> with Fenton Reagent

In this research Fenton reagent (Fe²⁺/H₂O₂) was investigated as oxidants to degrade poly (vinyl alcohol) (PVA). The role of nano-TiO₂ photocatalyst was discussed as an additive in Fenton reagent (Fe²⁺/H₂O₂). Pt/TiO₂ composites were also synthesized by photo-reaction to be used as additive in Fenton reagent. The rapid degradation of PVA was obtained when Pt/TiO₂ composites served as photocatalyst. The different photocatalytic efficiency of Pt/TiO₂- Fenton reagent (Fe²⁺/H₂O₂) was studied compared with TiO₂- Fenton reagent (Fe²⁺/H₂O₂) during the degradation of PVA.     

Effect of the Pretreatment with UV and Gamma Radiations on the Modification of Plywood Surface by Photocuring with Epoxy Acrylate

In order to further improve the physical properties of plywood surface that was pretreated with UV and Gamma radiation at different radiation intensities before photocuring. After pretreatment with radiation the plywood surface was coated with different prepared formulations containing epoxyacrylate (EA-1020) as an oligomer, difunctional monomers such as tripropylene glycol diacrylate (TPGDA), 2-hexadioldiacrylate (HDDA), Ethylene Glycol dimethacrylate (EGDMA) and trifunctional monomer trimethyl propen triacrylate (TMPTA) with photoinitiator Darocur 1664. Thin polymer films were prepared on glass plate with these formulated solutions and cured under UV radiation. Pendulum hardness (PH) and gel content of the film were studied for selecting the formulations as top coat and as base coat. The polished plywood surface was coated with selected formulation and cured under UV radiation. Various rheological properties of UV cured plywood surface such as pendulum hardness, scratch hardness, microgloss, adhesion strength, percentage chipped off area and abrasion resistance were studied.     

Characterizations of the Photocatalytically-Oxidized Cross-Linked Chitosan-Glutaraldehyde and its Application as a Sub-Layer in the TiO2/CS-GLA Bilayer Photocatalyst System

Photocatalytically-oxidized cross-linked chitosan-glutaraldehyde (CS-GLA) was obtained via irradiation of a simple assemblage of an immobilized layer-by-layer TiO₂/CS-GLA system on a glass plate with a 45-W fluorescent lamp. The oxidation process was observed to occur only in the presence of oxygen and TiO₂ within 5 cycles (10 h) of irradiation. Characterizations studies of the oxidized cross-linked polymer involving swelling index, pH-potentiometric titration and ionic conductivity measurements, as well as CHN, FTIR, ¹³C solid-state NMR,UV–Vis DRS and photoluminescence spectroscopy analyses generally indicated that the oxidation led to the formation of carbonyl groups, partial elimination of some un-reacted amino groups and change of visual color to be more brown without altering much of the whole molecular structure of the CS-GLA. This study also indicated that the photocatalytic performance of TiO₂/oxidized CS-GLA system was higher than both TiO₂/CS-GLA system and TiO₂ single layer for the removal of phenol. Moreover, the adsorption effect was extremely negligible and the photodegradation of phenol was mainly due to the photocatalytic process.     

Applying the Protective Role of Condensed Tannins to Acrylic-based Surface Coatings Exposed to Accelerated Weathering

Condensed tannins, extractable from tree bark have been assessed as functional additives to provide a protective role to acrylic-based coating resins. In addition to retaining high antioxidant capacity, the UV absorption properties of native and chemically modified tannins were found to be variously impacted by pH and degree of esterification or etherification. When added to acrylic-based coatings, these tannins were found to contribute colour to a white-base, but only small perceptive differences were found for clear coated wood using typical additive loadings of 0.1–0.4%. Integration of tannins in native or modified form to do not inhibit the cure of acrylic coatings or found to leach from cured coating films. Accelerated weathering was used to evaluate the photo-stability of tannin-modified acrylic and styrene-acrylic coatings. Native and modified tannins with maleate or methylcarboxylate groups retaining high antioxidant activity were associated with significantly greater coating longevity and performance than use of a synthetic photostabiliser. Moreover, esterified condensed tannins with a high degree of substitution also outperformed synthetic additives indicating the inherent UV absorption potential of these materials also contributed this efficacy within the acrylic and styrene-acrylic coating systems.     

Characterization and Properties of Hydrophilic Cellulose Acetate Propionate Derivative

The chemical modification of Acrylamidomethyl Cellulose Acetate Propionate (AMCAP) was carried out by radical addition of acrylic acid. The structural modification was confirmed with the aid of FTIR, MS and NMR techniques. Thermal properties of hydrophilic cellulose derivative (AMCAP–H₂O₂) such as glass transition (T_g 153 °C) and thermal stability (372.7 °C) were determined by DSC and TGA techniques, respectively. These thermal properties confirmed the introduction of carboxylic groups into AMCAP structure, which causes an impact in their properties. The AMCAP–H₂O₂ shows minor contact angle compared to AMCAP, giving a more hydrophilic characteristic, due to acrylic acid addition into the side chains of AMCAP polymer.     

Effect of Nanoscale SiO<Subscript>2</Subscript> and TiO<Subscript>2</Subscript> as the Fillers on the Mechanical Properties and Aging Behavior of Linear Low-Density Polyethylene/Low-Density Polyethylene Blends

Linear low-density polyethylene (LLDPE) was blended with low-density polyethylene (LDPE) at a fixed ratio (80 wt LLDPE and 20 wt %LDPE) and filled with nanoparticles of SiO₂ and TiO₂ at a ratio up to wt 5%, so as to develop the polymeric composites suitable to preparing the agricultural micro-irrigation pipes having good environmental adaptability. These compounds were blended using calcium stearate, polyethylene wax, and titanate coupling agent as the auxiliary dispersants, and ethylene-vinyl acetate copolymer (EVA) as the toughness improver. The LLDPE/LDPE composites filled with the nanoparticles were extruded and injected to prepare the composites specimens for the performance evaluations and micro-irrigation pipe field test. The mechanical properties, thermostability, and processibility of the injected composites were investigated. The effect of heating in an oven and irradiating by ultraviolet on the mechanical properties of the composites was explored. The environmental adaptability of the micro-irrigation pipes made of the filled LLDPE/LDPE composites was evaluated making use of long-term outdoor field test in northwest China where the arid and harsh natural conditions are of great concerns. It was found that the LLDPE/LDPE blend with the LLDPE mass fraction fixed as 80% showed balanced mechanical and thermal properties and flexibility, and was suitable to be used as the basic resin matrix. The incorporation of nano-TiO₂ contributed to effectively improving the resistance to heating and ultraviolet irradiation of the composites. The composite made from 91% basic resin matrix, 6% EVA, and 3% mixed nano-SiO₂ and TiO₂, showed balanced comprehensive properties. The micro-irrigation pipes made of this filled LLDPE/LDPE composite had good environmental adaptability and service behavior in a three-year field test and were suitable to be used in arid area.     

Performance and efficiency of old newspaper deinking by combining cellulase/hemicellulase with laccase-violuric acid system

Performance and efficiency of old newspaper (ONP) deinking by combining cellulase/hemicellulase with laccase-violuric acid system (LVS) were investigated in this study. Brightness, effective residual ink concentration (ERIC) and physical properties were evaluated for the deinked pulp. Fiber length, coarseness, specific surface area and specific volume were also tested. The changes of dissolved lignin during the deinking processes were measured with UV spectroscopy. The fiber morphology was observed with environmental scanning electronic microscopy (ESEM). Experimental results showed that, compared to the pulp deinked with each individual enzyme, ERIC was lower for the cellulase/hemicellulase-LVS-deinked pulp. This indicated that a synergy existed in ONP deinking using a combination of enzymes. After being bleached by H₂O₂, enzyme-combining deinked pulp gave higher brightness and better strength properties. Compared with individual enzyme deinked pulp, average fiber length and coarseness decreased a little for the enzyme-combining deinked pulps. A higher specific surface area and specific volume of the pulp fibers were achieved. UV analysis proved that more lignin was released during the enzyme-combining deinking process. ESEM images showed that more fibrillation was observed on the fiber surface due to synergistic treatment.     

Photocrosslinking of an Acrylated Epoxidized Linseed Oil: Kinetics and its Application for Optimized Wood Coatings

Over the past few decades, the industry developed an increasing interest in using renewable, bio-based thermosetting polymers as matrix systems for composites and coating systems. In the present paper an acrylated epoxidized linseed oil (AELO) was synthesized from epoxidized linseed oil (ELO) through ring opening of the oxirane group using acrylic acid as the ring opening agent. The synthesized AELO was mixed with three different photoinitiators and cured under monochromatic conditions (???=?365?nm) at different light intensities and at different temperatures. The concentration of the initiators was aligned that all initiators absorb at 365?nm the same amount of light. The evolution of cure was monitored by using real-time infrared spectroscopy with a heated attenuated total reflection unit. The decrease of absorption in the measured spectra at 1,406?cm^?1 was used to calculate the conversion of acrylic double bonds with increasing time of UV light exposure to get information about the cure kinetics for each AELO mixture at different light intensities and different temperatures. Wood substrates were coated in a preliminary work with the AELO mixtures and after UV-curing some technological coating properties like gloss, scratch resistance, adhesion, and solvent resistance were tested. In combination with the information about the cure kinetics in the present work the coating properties were correlated with the cure evolution and the final degree of double bond conversion. The found correlation can be used in the future to find optimized coating conditions for the AELO mixtures on wood substrates.     

Photochemical Degradation of Aqueous Polyvinyl Alcohol in a Continuous UV/H<Subscript>2</Subscript>O<Subscript>2</Subscript> Process: Experimental and Statistical Analysis

Polyvinyl alcohol (PVA), being a dominant contributor of total organic carbon (TOC) in textile wastewater, is not easily degradable by conventional methods of wastewater treatment. This study investigates the degradation of aqueous PVA in a continuous UV/H₂O₂ photoreactor since the feeding strategy of hydrogen peroxide proves to have considerable effects on the process performance. Response surface methodology involving the Box–Behnken method is adopted for the experimental design to study the effects of operating parameters on the process performance. Experimental analysis shows that the TOC removal varies from 16.11 to 42.70 % along with a reduction of the PVA molecular weights from 56.7 to 95.3 %. The TOC removal is significantly lower than the molecular weight reduction due to the generation of the intermediate products during oxidation. Operating the UV/H₂O₂ process in a continuous mode facilitates the degradation of highly concentrated polymeric solutions using a relatively small hydrogen peroxide concentration in the feed with a small residence time ranges from 6.13 to 18.4 min.     

Durability of PCL Nanocomposites Under Different Environments

The stability of PCL/TiO₂ nanocomposites under different environments was investigated. Samples were exposed to UV radiation in an accelerated weathering chamber equipment and characterized by viscosimetry and differential scanning calorimetry. The results showed that the presence of nanoparticles containing titanium enhanced polymer chain scission during UV exposure. For all samples, the melting temperature and crystallinity increased along photodegradation time. The biodegradability, assessed by biochemical oxygen demand, increased as the amount of inorganic particles increased. However, the thermal stability and activation energy evaluated by thermogravimetric analysis decreased as the amount of inorganic nanoparticles increased, indicating that nanocomposites exhibited lower thermal stability.     

Removal of Reactive Blue 19 dye from synthetic wastewater using UV/H2O2 and UV/Cl advanced oxidation processes

The textile and dyeing industries are among the largest water-consuming and polluting industries in the world. The most important feature of the textile dyeing industry wastewater is its color, due to the use of colored materials. Most of these dye compounds are resistant to conventional purification methods and their biodegradation is very low through secondary purification processes, resulting in incomplete removal. Therefore, selecting the optimal method to remove these color compounds is essential. In this study, we studied the removal of an organic dye contaminant (Reactive Blue dye 19 [RB19]) using advanced oxidation processes (AOPs). For this purpose, ultraviolet (UV) mercury lamps with a wavelength of 254 nm and a voltage of W16 inside a reactor were used as an energy source. The experiments were performed in a collimated beam reactor inside a dark chamber. Two oxidizers, sodium hypochlorite (NaOCl) and hydrogen peroxide (H₂O₂), were used to remove RB19 from the artificial sewage stream. Removal of RB19 with a concentration of 20 mg/L with variable pH (5, 7, and 9), oxidant concentrations (5, 10, and 20 mg/L), and time (5, 10, 15, and 30 min) were investigated during the processes of photolysis, chemical oxidation (by H₂O₂ and NaOCl), and UV/NaOCl and UV/H₂O₂ AOPs. The photolysis process did not remove the RB19. The highest removal efficiencies of RB19 by chemical oxidation processes with NaOCl and H₂O₂, UV/NaOCl, and UV/H₂O₂ at optimal conditions (pH = 5, [oxidant] = 20 mg/L, RB19 = 20 mg/L, and radiation intensity of 1005 mJ/cm²) were 64.49%, 0.88%, 99.7%, and 13.31%, respectively. These results indicate that the hydroxyl radical was produced, under optimum conditions, more in the acidic medium; thus, the RB19 removal efficiency was higher in the acidic medium. The combination of UV rays with oxidants resulted in the production of more hydroxyl radicals and increased removal efficiency.     

Effect of crystal size on zinc stabilization in aluminum-rich ceramic matrix

With aluminum as the predominant element, incineration residues from municipal solid waste and sewage sludge may be reused as precursors for zinc stabilization. As solid-state reactions are influenced by the crystal sizes of the reactants, the aluminum-containing components with different crystal sizes in the incineration residues may affect zinc transformation and immobilization. In this study, Al₂O₃ was prepared with a variety of crystal sizes to simulate the aluminum-rich incineration residue matrix, and ZnO was mixed with Al₂O₃ to study the zinc incorporation mechanisms. The crystal sizes of Al₂O₃ were determined using Rietveld refinement. Quantification results showed that ~?30% of zinc was incorporated into the ZnAl₂O₄ spinel when Al₂O₃ with the largest crystal size was used. However, the zinc transformation was enhanced twofold when the Al₂O₃ precursor had the smallest crystal size. This study confirmed the potential enhancement of zinc immobilization by nanoscale crystals in simulated aluminum-rich incineration residues. By improving zinc stabilization efficiencies using poorly crystallized aluminum-containing compounds instead of increasing the energy consumption by increasing the sintering temperatures, we can achieve an economic and environmental win–win scenario for the beneficial utilization of incineration residues of municipal solid waste and sewage sludge.     

A novel method for the preparation of silver/chitosan-O-methoxy polyethylene glycol core shell nanoparticles

Uniformly sized silver/chitosan-O-methoxy polyethylene glycol (chitosan-O-MPEG) core shell nanoparticles with different degree of substitution were synthesized. Thus, N-phthaloyl chitosan is reacted with polyethylene glycol monomethyl ether iodide in the presence of silver oxide by the following steps. At first, amino groups of chitosan are protected by fourfold excess of phthalic anhydride. Then N-phthaloyl chitosan is reacted with an appropriate amount of monomethyl ether iodide in the presence of silver oxide and lastly N-phthaloyl groups are removed to yield silver/chitosan-O-MPEG core shell nanoparticles. Structure of prepared silver/chitosan-O-MPEG core shell nanoparticles have been characterized by UV/Vis spectroscopy, transmission electron microscopy (TEM), Fourier transform infrared (FT-IR), X-ray diffraction, and scan electron microscopy (SEM-EDX). Experimental results revealed that the prepared silver core particles had the size 18?±?2?nm. Core shell structure with chitosan-O-MPEG-coating had the size 40?±?2?nm.     

Behavior of TiO2 nanoparticles during incineration of solid paint waste: A lab-scale test

In order to assess the potential impacts posed by products containing engineered nanoparticles, it is essential to generate more data about the release of these particles from products’ life cycle. Although first studies were performed to investigate the release of nanoparticles from use phase, very few data are available on the potential release from recycling or disposal of nano-enhanced products.In this work, we investigated the behavior of TiO₂ nanoparticles from incineration of solid paint waste containing these particles. Solid paint debris with and without TiO₂ nanoparticles were treated in a lab scale incineration plant at 950 °C (combustion temperature) and in oxidizing atmosphere. The obtained ashes were also vitrified with additives and the release of Ti was finally evaluated by leaching test. From our incineration lab-scale experiment, we did not observe a release of TiO₂ nanoparticles into the atmosphere, and Ti was attached to the surface of obtained solid residues (i.e. ashes). The characterization of ashes showed that TiO₂ nanoparticles reacted during the incineration to give calcium titanate. Finally, a very low release of Ti was measured, less 1 mg/kg, during the leaching test of ashes vitrified with glass cullet and feldspathic inert. Our work suggests that TiO₂ nanoparticles added in paints may undergo to physicochemical transformation during the incineration, and that Ti found in ashes may be strongly immobilized in glass matrix. Since this conclusion is based on lab-scale experiment, further research is required to identify which nanoparticles will be emitted to the environment from a real-word-incineration system of household hazardous waste.     

The use of the removable thin film coating technique as an alternative to traditional decontamination methods to mitigate and abate hazardous particulates

This article summarizes a study that evaluated a new decontamination technique for the mitigation and abatement of hazardous dust and particulates. Traditional decontamination methods are time‐consuming, expensive, can create airborne hazards, and do not always bring the concentration of the contaminant to acceptable levels. The use of the removable thin film coating will increase efficiency, will not generate airborne hazards, will decrease costs, and, with one application, will bring the hazardous dust concentrations to acceptable levels. Qualitative tests demonstrated that the removable thin film coating reduced the amount of visible luminescent dust (a surrogate for hazardous dust) from various surfaces. It also indicated that wherever there were minute scratches, the coating did not remove all of the dust. However, the qualitative tests showed that this decontamination method worked well as a preventative method, protecting clean areas from becoming contaminated when exposed to the luminescent dust. Further investigation was conducted using a scanning electron microscope (SEM) and carbon dust. Overall, the SEM experiment demonstrated that there was a statistically significant (p = 0.00007) removal of carbon dust (less than 10 μm in size) from surfaces with crevasses larger than 3 μm. The SEM also revealed that there were some limitations where there were large clusters of carbon dust; in these instances, the coating would tear and remain on the sample surface. One method to resolve this limitation involved adding Kevlar^TM fibers to the removable thin film coating. It was thought that this would increase the strength of the coating and eliminate the coating from tearing when removing large clusters of a contaminant. Unfortunately, this did not alleviate the issue. The use of an engineered textile, saturated with the coating, appeared to eliminate the problem with the coating not being able to remove the contaminant from the minute surface scratches and improved the removal process of the coating. © 2008 Wiley Periodicals, Inc.