Infrared Ray Spectrum Research Articles

Polymer-Based Nano-Adsorbent for the Removal of Lead Ions: Kinetics Studies and Optimization by Response Surface Methodology

This work successfully created a polypyrrole-polyethyleneimine (PPy-PEI) nano adsorbent for the elimination of the lead ion Pb2+ from an aqueous solution. An efficient conducting polymer-based adsorbent called as was created using ammonium persulfate (NH4)2S2O8 as an oxidant (PPy-PEI). The PEI hyper-branched polymer with terminal amino groups was added to the PPy adsorbent to offer heavy metals more effective chelating sites. Pb2+ removal from aqueous solution using polyethyleneimine micro adsorbent was successfully accomplished using a batch equilibrium technique (PPy-PEI). The generated water-insoluble polymer nanoadsorbent had enough nitrogen atoms; therefore, an effort was made to link PEI, a water-soluble PPy, with PPy, a conjugated polymer, for lead ion adsorption from an aqueous solution. The generated PPy-PEI nanoadsorbents were discovered to have average particle sizes of 18–34 nm and a Brunauer-Emmet-Teller surface area of 17 m2/g, respectively. The thermal behavior of the composites was investigated using thermo gravimetric and differential scanning calorimetric methods. The lead ion adsorption efficacy of pure polypyrrole was found to be 38%; however, a batch equilibrium technique employing nanoadsorbent revealed with the maximum adsorption capacity of 75.60 mg g−1. At pH 10 and 30 min of contact time at 50 °C, 0.2 g of adsorption was shown to be the ideal dosage. X-ray diffraction analysis, energy-dispersive ray spectroscopy, and Fourier transform infrared ray spectrum support the lead ion adsorption by PPy-PEI nanoadsorbents. The cauli-like structure was visible using field emission scanning electron microscopy. Studying the thermodynamic showed that the adsorption was endothermic as illustrated from the positive value of value of ΔH° is 1.439 kJ/mol which indicates that the uptake of Pb2+ onto nanoadsorbent PPy-PEI could be attributed to a physical adsorption process. According to the values of ΔG°, the adsorption process was spontaneous at all selected temperatures. The positive value of ΔS° value (43.52 j/mol) suggested an increase in the randomness at the solid/solution interface during the adsorption process. The adsorption data meet the pseudo-second-order kinetic model and suited the Langumuir isothermal model effectively.

A new technology for separation and recovery of materials from waste printed circuit boards by dissolving bromine epoxy resins using ionic liquid

Recovery of valuable materials from waste printed circuit boards (WPCBs) is quite difficult because WPCBs is a heterogeneous mixture of polymer materials, glass fibers, and metals. In this study, WPCBs was treated using ionic liquid (1-ethyl-3-methylimizadolium tetrafluoroborate [EMIM+][BF4−]). Experimental results showed that the separation of the solders went to completion, and electronic components (ECs) were removed in WPCBs when [EMIM+][BF4−] solution containing WPCBs was heated to 240°C. Meanwhile, metallographic observations verified that the WPCBs had an initial delamination. When the temperature increased to 260°C, the separation of the WPCBs went to completion, and coppers and glass fibers were obtained. The used [EMIM+][BF4−] was treated by water to generate a solid–liquid suspension, which was separated completely to obtain solid residues by filtration. Thermal analyses combined with infrared ray spectra (IR) observed that the solid residues were bromine epoxy resins. NMR (nuclear magnetic resonance) showed that hydrogen bond played an important role for [EMIM+][BF4−] dissolving bromine epoxy resins. This clean and non-polluting technology offers a new way to recycle valuable materials from WPCBs and prevent environmental pollution from WPCBs effectively.

A new alkali-activated steel slag-based cementitious material for photocatalytic degradation of organic pollutant from waste water

A new type of Ni,Ca-cementitious material was firstly synthesized via a two-step reaction of alkali-activated steel slag polymerization and ion exchange. The XRF results showed that almost all the Na+ ions in the matrix of Na,Ca-cementitious material were replaced by Ni2+ ions at room temperature. The new hydrated products of metahalloysite (Si2Al2O5(OH)4) and calcium silicate hydrate (CSH) were formed in the Na,Ca-cementitious material. The diffuse reflectance UV–vis near infrared ray spectrum was blue-shifted due to the strong interaction between Ni2+ and negative charge of [AlO4]5− tetrahedron in the framework of cementitious material. The Ni,Ca-cementitious material was used as a catalyst for the photocatalytic degradation of methylene blue dye and showed a degradation rate of 94.39% under UV irradiation. The high photocatalytic degradation activity was suggested to be the synergistic effect of the cementitious matrix, Ni2+ ions and the iron oxides of wustite (FeO) and calcium iron oxide (Ca2Fe2O5) from the steel slag. A probable mechanism of photocatalytic oxidative degradation was proposed.

Adsorption behaviors of a novel carbonyl and hydroxyl groups modified hyper-cross-linked poly(styrene-co-divinylbenzene) resin for β-naphthol from aqueous solution

A series of novel hyper-cross-linked resins were synthesized from macroporous cross-linked chloromethylated poly(styrene-co-divinylbenzene) by adding different dosage of hydroquinone in Friedel-Crafts reaction. The results of the pore structures revealed that the prepared resins possessed micropores, mesopores and macropores, and the chloromethyl groups and the uploaded hydroquinone were partly oxidized according to the results of Fourier-transformed infrared ray spectra. Among these hydroquinone modified resins, HJ-Y06 resin held the largest adsorption capacity for β-naphthol, and its adsorption capacity was comparable with XAD-4 while much larger than X-5. The adsorption kinetics could be characterized by pseudo-second-order rate equation and intra-particle diffusion model was the rate-limiting step at the initial process. The adsorption was favorable at solution pH lower than 6.5. The adsorption isotherms could be fitted by Langmuir model and the adsorption was an endothermic process. Hydrogen bonding between formaldehyde carbonyl and quinone carbonyl groups on HJ-Y06 and phenolic hydroxyl groups of β-naphthol was the main driving force for the adsorption.

Biosorption of Copper by Cyanobacterial Bloom-Derived Biomass Harvested from the Eutrophic Lake Dianchi in China

Biomass of cyanobacterial bloom from Lake Dianchi was used as a biosorbent for copper removal from aqueous solution. The maximum capacity was found at conditions of pH 4, initial concentration of copper was 10mg/l and initial dose of biomass was 1.0g/l. HNO(3) demonstrated the highest desorption efficiency compared with HCl, EDTA, and citric acid. Physical adsorption was assumed not to be the dominant mechanism of biosorption as revealed by scanning electron microscopy and surface area measurement of the biomass. Infrared ray spectra analysis of the biomass suggested that ion-exchange is the principal mechanism for biosorption. Considering the advantages-low cost, easy to collect, and huge in quantity-the Microcystis bloom biomass could be used as a sorbent for copper and other heavy metals removal.

Synthesis of acrylate microemulsion modified by alkoxy silane

An acrylate emulsion was modified by adding vinyltriisopropoxy silane (trade name C-1706). By adding the multiple emulsifier which consists of an anionic emulsifier, sodium dodecyl benzene sulfonate (SDBS) and nonionic emulsifier, octyl phenolic divinyl oxide (OP-10), the acrylosilane microemulsion was synthesized by seeded emulsion polymerization. The influential factors including the kind and the adding amount of emulsifiers and the monomer variety of alkoxy silane and the added methods which influence on the properties of the microemulsion were investigated. It is found that SDBS and OP-10 as multiple emulsifiers with mass ratio of 1:1 and the adding amount of 2.5%–3.5% can act on co-effect for emulsion polymerization. The C-1706 possesses bulky isopropoxy substituent that can reduce hydrolysis reactivity during the polymerization process, so as to not only make the process smoothly but also advance the store stability of the emulsion. Moreover, the latter-addition mode of C-1706 can restrain its hydrolysis activity and polycondensation reaction during the polymerization process of the emulsion. The structure, the film cross section, the particle size and its distribution of the microemulsion were analyzed by the Fourier Transform Infrared Ray Spectrum (FTIR), Scanning Electron Microscopy (SEM) and a particle size analyzer,respectively. The results show that the particle diameter of the modified microemulsion can be controlled between 50 and 70 nm and its film hardness is 7.3. Only adding 1.5% of C-1706 into the system of emulsion polymerization can apparently improve the weathering resistance of the microemulsion, which undergo degradation with chromatism(ΔE) is 1.6 after 3 600 hours of QUV-aging.

Preparation and Testing of Cementing and Coating Nano-Subnanocomposites of Slow/Controlled-Release Fertilizer

To select the cementing and coating materials of slow/controlled-release fertilizer, the natural kaoline and abandoned foam plastics were used to prepare nano-subnanocomposites through the methods of organic material intercalation, semiemulsification, and cut at high velocity techniques. Besides, two kinds of nano-subnanocomposites were tested in this study using several instruments, including the scanning electron microscope (SEM), the X-ray diffraction (XRD), the infrared ray spectrum (IR), and the laser granularity. The main results were as follows: 1) The organic material was intercalated in the layers of kaoline clays, and the natural kaoline exfoliated into nanometer-sized layers. The organic agent and clays formed nanocomposites through hydrogen bond combination. 2) The SEM pictures of polystyrenestarch nano-subnanocomposites showed that many pores and rugas were present on the surface of film at sizes ranging from 10 to 20 nm. These nano-subnanocomposites were used as the cementing and coating materials of slow/controlled-release fertilizer.

Crosslinking of cotton cellulose in the presence of serine and glycine. I. Physical properties and reaction kinetics

AbstractSerine and glycine were used to combine with dimethyloldihydroxyethyleneurea (DMDHEU) as crosslinking agents to study the physical properties of the crosslinked fabrics and the reaction kinetics, and find that the bound nitrogen is in the series of DMDHEU ≫ DMDHEU‐serine > DMDHEU‐glycine at the same resin concentration. The results also show that the wet crease recovery angle (WCRA) value of the treated fabrics for the three crosslinking agent systems is in the series of DMDHEU‐serine > DMDHEU‐glycine > DMDHEU alone at a given dry crease recovery angle (DCRA). The DCRA values of the treated fabrics for DMDHEU alone are higher than those for DMDHEU‐α‐amino acids for a given value of tensile strength retention (TSR). WCRA values for the various treated fabrics is in the rank of DMDHEU‐serine > DMDHEU alone > DMDHEU‐glycine at the same TSR. Rate constants for the various crosslinking agents are in the series of DMDHEU‐glycine > DMDHEU‐serine > DMDHEU alone at the given heated temperatures. Energies needed to crosslink and the values of enthalpies and entropies of activation are all DMDHEU‐glycine > DMDHEU‐serine > DMDHEU alone. Infrared ray (IR) spectra strongly suggest the reaction between DMDHEU and serine and the reaction between the hydroxyl group (cellulose) and serine can occur in the pad‐dry‐cure process, but only a little for the latter. The reaction between the functional groups of serine and the aluminum ion to form a complex also confirm with IR spectrum. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 595–603, 2005

Nanocrystalline structure and magnetic properties of barium ferrite particles prepared via glycine as a fuel

The barium ferrite particles were prepared using a self-propagating combustion method with glycine as a fuel. The process was investigated with differential scanning calorimeter and thermogravimetric analysis. The effects of the pH value of the precursor solution, the glycine dosage and calcination temperature on the morphology, the crystalline structure and the magnetic properties of the barium ferrite particles were studied by means of X-ray diffraction, infrared ray spectra, field emission scanning electron microscopy and vibrating sample magnetometry. The results show that the ignition temperature of glycine gel is lower than that of citric acid gel. The pH value of the precursor solution greatly affects the crystal structure of powders after combustion and calcination. Barium hexaferrite particles with a specific saturation magnetization of 56.1 A m 2/kg and a coercivity of 398.0 kA/m were obtained when the pH value of the precursor solution was 7.0 and the calcination temperature was 850 °C.

Surface micromachining and characterization of a pyroelectric infrared ray focal plane array utilizing SiO2 as the IR absorbing layer

The development of a surface micromachined infrared ray (IR) focal plane array (FPA), in which a single SiO2 layer functions as an IR absorbing plate and a Pb(Zr0.3Ti0.7)O3 thin film serves as a thermally sensitive material is described. The advantages of using SiO2 as an IR absorbing layer include the fact that it has good IR absorbance within the 8–12 µm spectral range. In this case, about 60% of the incident IR spectrum in this range was absorbed. Another important advantage of SiO2, when applied to the top of the Pt/PZT/Pt stack, is that it functions as a supporting membrane. Consequently, the IR absorbing layer forms as one body on the membrane structure, which simplifies the overall MEMS process and provides a robust structure.