MUF Resins Improved by Citric Acid as Adhesives for Wood Veneer Panels

This article presents the first applied results of using citric acid in combinations with a melamine-urea-formal-dehyde(MUF)resin for bonding wood veneers.The chemical reactions involved are shown based on a MALDI ToF analysis of the reaction of the MUF resin with citric acid.The preliminary results of the physical and mechanical properties of the LVL prepared are also presented.Veneers from Populus sp were used to manufacture 5-layer laminated veneer lumber(LVL)of small dimensions.Five combinations of the amount of citric acid,MUF spread rate and pressing parameters were tested.LVL bonded with 20%of citric acid+100 g/m^(2)of MUF,hot-pressed using a 3-step process with maximum 1.5 MPa of pressure yielded the board with better dimensional stability and mechanical properties.It could be concluded that citric acid in combination with MUF can be used for bonding wood veneer and the research should be continued to study further the parameters involved and to enhance the results.

Adsorption of Er(Ⅲ ) and Its Mechanism on Diglycolamidic Acid Resin

The adsorption behavior and mechanism of a novel chelate resin, diglycolamidic acid resin (DAAR) for Er(Ⅲ) were investigated. The optima adsorption condition of DAAR for Er(Ⅲ) is pH 6.20 in HAc NaAc medium. The statically saturated adsorption capacity is 189 mg·g -1 resin at 298 K. The Er (Ⅲ) adsorbed on DAAR can be eluted reaching 100% by 2 mol·L -1 HCl used as eluant. The resin can be regenerated and reused without apparent decreasing of adsorption capacity. The apparent adsorption rate constant is k 298 =1.94×10 -5 s -1 . The apparent activation energy is 24.7 kJ·mol -1 . The adsorption behavior of DAAR for Er(Ⅲ) obeys the Freundlich isotherm. The thermodynamic adsorption parameters, enthalpy change Δ H of DAAR for Er(Ⅲ) is 24.1 kJ·mol -1 . The molar coordination ratio of the functional group of DAAR to Er (Ⅲ) is 3∶1. The adsorption mechanism of DAAR for Er (Ⅲ) was examined by using chemical method and IR spectrometry. The coordination compound is formed between oxygen atoms in the functional group of DAAR and Er(Ⅲ).

Studies on Adsorption Behavior and Mechanism of Copper(Ⅱ) onto Amino Methylene Phosphonic Acid Resin

The adsorption behavior and the mechanism of a novel chelate resin, amino methylene phosphonic acid resin(APAR) for Cu(Ⅱ) were investigated. Cu(Ⅱ) was quantitatively adsorbed by APAR in the medium of pH=4 09. The statically saturated adsorption capacity is 181 mg/(g resin). Cu(Ⅱ) adsorbed on APAR can be eluted by 1 0-3 0 mol/L HCl. The rate constant is k 298 =5 58×10 -5 s -1 . The adsorption of Cu(Ⅱ) on APAR follows the Freundlich isotherm. The Δ H of the adsorption is 3 91 kJ/mol. The apparent activation energy is E a=21 4 kJ/mol. The coordination molar ratio of APAR to Cu(Ⅱ) is 1/1. It is shown that the nitrogen and the oxygen atoms in the functional group of APAR coordinate to Cu(Ⅱ).

Mechanism and kinetics study on removal of Iron from phosphoric acid by cation exchange resin

Iron element is one of the main impurities in wet-process phosphoric acid and it has a significant impact on the subsequent phosphorus chemical products. This paper studied the feasibility of using Sinco-430 cation exchange resin for iron removal from phosphoric acid. The specific surface area and the total exchange capacity of resin were 8.91 m2·g-1 and 5.18 mmol·g-1, respectively. The sorption mechanism was determined by FTIR and XPS and the results indicated that iron was combined with-SO3 H in resin. The removal process was studied as a function of temperature, H3 PO4 content and mass ratio between resin and solution. The unit mass of resin to remove iron was 0.058 g·g-1 resin when the operating parameters were T = 50 ℃, H3 PO4 content = 27.61 wt%and S/L = 0.1, respectively. Kinetics study demonstrated that pseudo-second-order reaction model fits this study best and the calculated activation energy of overall reaction is 29.10 kJ·mol-1. The overall reaction process was mainly controlled by pore diffusion.

Sorption Behavior and Mechanism of Indium(Ⅲ) onto Amino Methylene Phosphonic Acid Resin

The sorption behavior of amino methylene phosphonic acid resin (APAR) for In (Ⅲ ) was investigated . Experimental results show that In ( Ⅲ ) adsorbed on APAR can be elated with 2mol · L -1 HCl. The apparent rate constant is k29 = 1.50 × 10-5s-1. The sorption behavior of APAR for In ( Ⅲ ) obeys the Freundlich isotherm. The themodynamic parameters of sorption, enthalpy change ()H, free energy change ()G and entropy change ()S of sorption (APAR) for In ( Ⅲ ) are 24.1 kJ·mol-1, -35. 1kJ· mol-1 and 200J· mol-1·K-1 respectively. The coordination molar ratio of the functional group of APAR to In( Ⅲ ) is 2:1. The sorption mechanism of APAR for In( Ⅲ ) was examined by IR spectrometry.

ADSORPTION STUDIES OF TANNIC ACID BY COMMERCIAL ESTER RESIN XAD-7

Tannic acid and its related compounds are known as refractory organic pollutants, and it can create serious problems for the environment. The adsorption and desorption studies of tannic acid on commercial resins XAD-7 and D-201 are performed, and all data indicates resin XAD-7 can be used as an effective adsorbent for removing tannic acid during water/wastewater treatment. Furthermore, adsorption thermodynamics studies indicate different adsorption mechanisms for TA on XAD-7 and D-201. FT-IR and solid state 13C-NMR spectroscopy are used to explain the adsorption force between XAD-7 and TA. It suggests that hydrogen bonding is the main adsorption force for TA. Finally, XAD-7＇s adsorption capacity in the presence of different metal ions is investigated, which indicates that heavy metal ions in solutions can decrease the adsorption capacity for TA on ester resin XAD-7.

A convenient synthesis of pyrroles catalyzed by acidic resin under solvent-free condition

A convenient and effective Paal-Knorr condensations of 2,5-hexanedione with most amines have been carried out at room temperature under solvent-free condition.Macroporous strongly acidic styrol resin(D001) as a novel,efficient,cost-effective,and reusable solid acid catalyst for the synthesis of pyrroles under the same conditions.The pyrroles were obtained in high yields in short reaction times.

Adsorption of β-naphthalenesulfonic acid/sulfuric acid from their solution by weakly basic resin:equilibrium

Experiments for single and bisolute competitive adsorption were carried out to investigate the adsorption behavior of β-naphthalenesulfonic acid(NSA) and sulfuric acid (H_2SO_4) from their solution at 25℃ onto weakly basic resin D301R. Adsorption affinity of sulfuric acid on D301R was found to be much higher than that of NSA. The data of single-solute adsorption were fitted to the Langmuir model and the Freundlich adsorption model. The ideal adsorbed solution theory(IAST) coupled with the single-solute adsorption models were used to predict the bisolute competitive adsorption equilibria. The IAST coupled with the Langmuir and the Freundlich model for sulfuric acid and NSA, respectively, yields the favorable representation of the bisolute competitive adsorption behavior.

Adsorption of Macroporous Phosphonic Acid Resin for Nickel

Tje adsorption bchavior and mechanism of a novel chelate resin,macroporous phosphonic acid resin（PAR）for Ni（Ⅱ）were imestigated.The stotically saturated adsorption capacity is 64.3mg·g^-1 resin at 298K in HAc-NaAc medium.The Ni（Ⅱ）adsorbed on PAR can be eluted by 0.5mal·L^-1 HCl and the elution percentage reaches 96.6%.The resin can be regenerated and reused without abvious decrease in adsorption capacity.The apparent adsorption rate constant is k298=2.6×10^-5s^-1.The adsorption behavior of PAR for Ni（Ⅱ）obeys the Freundllich isotherm.The thermodynamie adsorption parameters.enthalpy change △H,free energy change △G and entropy change △S of PAR for Ni（Ⅱ）are 3.36kJ·mol^-1,-5.47kJ·mol^-1 and 29.6J·mol^-1·K^-1,respectively.The apparent activation energy is Ea=12.2kJ·mol^-1,The molar coordination ratio of the functional group of PAR to Ni（Ⅱ）is about 4：1.The adsorption mechanism of PAR for Ni（Ⅱ）was examined by a chemical method and IR spectrometry.

SYNTHESES AND ADSORPTION PROPERTIES OF PHENOL-FORMALDEHYDE-TYPE CHELATING RESINS BEARING THE FUNCTIONAL GROUP OFTAR TARIC ACID

Several kinds of novel chelating resins bearing the functional group of tartaric acid (TTA-FQ-12, TTA-FQ-23, and TTA-FQ-34) were synthesized by reacting epoxy maleic anhydride, which was prepared through the oxidization reaction of maleic anhydride by hydrogen peroxide, with phenol-formaldehyde resin containing polyamine (FQ resins series). The effects of such factors as reaction time, reaction temperature and pH value on the loading capacity of TTA in resins were investigated. The results showed that the optimum reaction conditions are as follows: time 9-12 h; temperature 90-105'C; pH value 6-10. The loading capacities of TTA can reach 0.15, 0.14, and 0.11 mmol/g-1 when the functional group of FQ resin was - OCH2CH2NHC2H4NH2, - O(CH2CH2NH)2C2H4NH2 and - O(CH2CH2NH)3C2H4NH2), respectively. The structures of resins were characterized by FTIR spectra. The primary study on the adsorption properties of the resins for metal ions showed that there are two kinds of adsorption mechanisms i.e. ion exchange and chelate in the adsorption process. TTA-FQ resins have much higher adsorption selectivity for Pb2+and Zn2+ than for Cu2+ and Ni2+. These resins can probably be used for separating Pb2+ or Zn2+ in the mixture of metal ions or for treating wastewater containing heavy metal ions.

ADSORPTION OF TANNIN ACID ONTO AN AMINATED MACROPOROUS RESIN FROM AQUEOUS SOLUTIONS

A macroporous polymeric adsorbent NG-8 was synthesized with divinylbenzene using conventional suspension polymerization technique. Its aminated product NG-9 was prepared by introducing tertiary amino groups into NG-8 for removal of tannin acid from aqueous solutions. NG-9 could be used directly without a wetting process and had higher adsorption capacity than NG-8, which might be attributed to the enhanced adsorbent-adsorbate interaction due to the tertiary amino groups on the polymeric matrix. The Langmuir equation was successfully employed to describe the adsorption process. The adsorption enthalpy change further validated the uptake of tannin acid on NG-9 to be an enhanced physical adsorption because of the Lewis acid-base interaction. In addition, adsorption kinetic studies testified that the tertiary amino groups on the polymer matrix could decrease the adsorption rate maybe for the hindrance of the tertiary amino groups and water clusters built up.

Adsorption Behaviors and Mechanism of Macroporous PhosphonicAcid Resin for Gadolinium

The adsorption behaviors and mechanism of a novel chelate resin, macroporous phosphonic acid resin(PAR)for Gd(Ⅲ)were investigated. The statically and dynamically saturated adsorption capacity is respectively 308 mg·g^(-1)resin and 296 mg·g^(-1)resin at 298 K in HAc-NaAc medium at pH 5.6. Gd(Ⅲ)adsorbed on PAR can be reductively eluted by 0.5～5.0 mol·L^(-1) HCl used as eluant and the elution percentage is up to 94.7% in 1.0 mol·L^(-1) HCl. The resin can be regenerated and reused without apparent decrease in adsorption capacity. The apparent adsorption rate constant is k_(298)=3.96×10^(-5) s^(-1). The adsorption behavior of PAR for Gd(Ⅲ) conforms to the Freundlich isotherm. The thermodynamic adsorption parameter, enthalpy change △H of PAR for Gd(Ⅲ)is 22.6kJ·mol^(-1). The apparent adsorption activation energy(Ea)of PAR for Gd(Ⅲ)is 5.0 kJ·mol^(-1). The molar coordination ratio of the functional group of PAR to Gd(Ⅲ)is about 3∶1. The adsorption mechanism of PAR for Gd(Ⅲ)was examined by using chemical method and IR spectrometry.

Studies on the Adsorption of Amino Methylene Phosphonic Acid Resin for Holmium(Ⅲ)

The adsorption behavior and mechanism of a novel chelate resin, amino methylene phosphonic acid resin (APAR) for Ho(Ⅲ) were investigated. The statically saturated adsorption capacity is 258 mg·g^(-1) resin at 298 K in HAc-NaAc medium. The Ho(Ⅲ) adsorbed on APAR can be repeatedly eluted by 3.0 mol·L^(-1) HCl and the elution percentage is as high as 95.8%. The resin can be regenerated and reused without apparent decrease in adsorption capacity. The apparent adsorption rate constant is k_(298)=1.14×10^(-5) s^(-1). The adsorption behavior of APAR for Ho(Ⅲ) obeys the Freundlich isotherm. The thermodynamic adsorption parameter, enthalpy change ΔH of APAR for Ho(Ⅲ) is 11.4 kJ·mol^(-1). The apparent activation energy is E_a=15.8 kJ·mol^(-1). The molar coordination ratio of the functional group of APAR to Ho(Ⅲ) is about 2∶1. The adsorption mechanism of APAR for Ho(Ⅲ) was examined by using chemical method and IR spectrometry.

Adsorption behavior and mechanism of amino methylene phosphonic acid resin for Ag(Ⅰ)

The sorption properties of amino methylene phosphonic resin(APAR) for Ag(Ⅰ) were studied. The amino methylene phosphonic acid resin(APAR) has a good adsorption ability for Ag(Ⅰ) at pH=6.0 in the HAc-NaAc medium. The statically saturated adsorption capacity is 272 mg/g resin, Ag(Ⅰ) adsorbed on APAR can be eluted by 5% (NH2)2CS-0.5 mol/L hydrochloric acid quantitatively. The adsorption rate constants determined under various temperatures are k15℃=3.89×10?5 s?1, k25℃=5.93×10?5 s?1, k35℃=7.59×10?5 s?1, k45℃=9.45×10?5 s?1, respectively. The apparent activation energy of adsorption, Ea is 22.8 kJ/mol, the enthalpy change (?H) of sorption is 17.4 kJ/mol. The adsorption mechanism shows that the functional group of APAR coordinates with Ag(Ⅰ) to form coordination bond, the coordination molar ratio of the functional group of APAR to Ag(Ⅰ) is 1∶1.

Study on the influence of humic acid of different molecular weight on basic ion exchange resin's adsorption capacity

在这篇论文，腐殖的酸(哈) 是进不同分子的重量节的 ultra-filtered 并且被多元素分析，紫外 254/TOC, 英尺红外和三维的荧光描绘度谱。因为不同分子的重量的腐殖的酸有不同吸水、分子的尺寸，基本离子交换树脂的最大的吸附能力在其分子的重量从 6000 ～ 10,000 Da 的腐殖的酸上出现。

Purification of Lactic Acid by Heterogeneous Catalytic Distillation Using Ion-exchange Resins

The purification of lactic acid based on the esterification of raw lactic acid from fermentation broth and then the catalytic distillation hydrolysis of methyl lactate simultaneously to achieve pure lactic acid is reported. The esterification kinetics of lactic acid with methanol catalyzed by strong-acid cation-exchange resins (Amberlyst-15,D001, D002, NKC, 002) was studied under the condition that simulates the real catalytic environment. Experimental results were correlated by a Langmuir-Hinselwood model and the nonideality of the solution was taken into account by using activities calculated by the universal quasichemical functional group activity coefficient (UNIFAC) method.A good agreement between the model and the experimental data was achieved. Continuous purification experiments were conducted to find the optimum column configuration and operation condition for the system. The effects of various parameters, e.g. the length of different section of the column, feed rate and ratio of reactants, packing material and catalyst type, were studied. This novel system shows good separation results in lab scale, and is potential for industrial application.

DCHA AS A NEW REAGENT FOR THE ESTERIFICATION OF OBSTINATED AMINO ACIDS BY THE MERRIFIELD'S RESIN

The obstinated amino acid,Boc-Asn(or Boc-Gln),was directly anchored onto the Merrifield's resin using DCHA as the base in present reaction.The yield(71.88%)of Boc-Asn-OCH_2-resin was much better than those(0-33.5%)using Cs_2CO_3,KOH,KF.DEA and TEA as the base.which are efficient reagents for other amino acids in the same reaction.

Adsorption of β-Naphthalenesulfonic Acid/Sulfuric Acid from Their Solution by Weakly Basic Resin

Experiments for single and bisolute competitive adsorption were carried out to investigate the adsorption behavior of β-naphthalenesulfonic acid(NSA and sulfuric acid from their solution at 25℃ onto weakly basic resin D301R,Adsorption affinity of sulfuric acid on D301R was found to be much higher than that of NSA.The data of single-solute adsorption were fitted to the Langmuir model and the Freundlich adsorption model.The ideal adsorbed solution theory(IAST) coupled with the single-solute adsorption models were used to predict the bisolute competitive adsorption equilibria.The IAST coupled with the Langmuir and the Freundlich model for sulfuric acid and NSA.Respectively,yields the favorable representation of the bisolute competitive adsorption behavior.

Adsorption behavior and mechanism of cadmium on strong-acid cation exchange resin

The adsorption behavior of Cd2+ on 001×7 strong-acid cation exchange resin was studied with the static adsorption method. The adsorption process was analyzed from thermodynamics and kinetics aspects. The influences of experimental parameters such as pH, temperature, initial concentration and adsorption rate were investigated. The experimental results show that in the studied concentration range, 001×7 resin has a good sorption ability for Cd2+, and the equilibrium adsorption data fit to Freundlich isotherms. The adsorption is an exothermic process which runs spontaneously. Kinetic analysis shows that the adsorption rate is mainly governed by liquid film diffusion. The best adsorption condition is pH 4-5. The saturated resin can be regenerated by 3 mol/L nitric acid, and the desorption efficiency is over 98%. The maximal static saturated adsorption capacity is 355 mg/g (wet resin) at 293 K. The adsorption mechanism of Cd2+ on 001×7 resin was discussed based on IR spectra.