Adsorption of Heavy Metal Salts by Cotton Fabrics Containing Polyethylene and Polypropylene Sulfide

The adsorption of mercury and other heavy metal salts by cotton fabrics containing polyethylene and polypropylene sulfide was investigated. Adsorption of mercuric chloride from aqueous solution was investigated in detail, and AH of the reaction was determined. A general screening of the capacity of adsorption of the polymers for heavy metal salts was carried out. Differences in behavior between the polymeric system and simple thioethers were observed. Auric, antimony, titanium, palladium, platinum and bismuth salts were adsorbed by the modified cotton; other salts, known also to complex with organic sulfides, were not adsorbed.     

Effects of acceptor level on chemically synthesized polypyrrole-halogen complexes

Electrically conductive polypyrrole (PPY)-halogen complexes have been synthesized by simultaneous chemical polymerization and oxidation of pyrrole. The ratio of pyrrole monomer to halogen (chlorine, bromine, or iodine) used in the synthesis was varied and the physicochemical and electrical properties of the resulting complexes were studied in detail. With all three halogens, the yield of the complex is affected by the initial amount of halogen used, with the properties of the polypyrrole-bromine complex showing the strongest dependence on the acceptor level. For this complex, both the percentage of bromine incorporated and the ratio of covalent to ionic bromide increase upon increasing the initial bromine concentration, while the electrical conductivity shows a maximum. Experimental evidence suggests that some halogen substitution at the pyrrole ring must have occurred in the PPY–Br₂ and PPY–Cl₂ complexes, but not in the PPY–I₂ complex.     

Functional monomers and polymers, 85. On the adsorption of bromine onto chitosan

The adsorption of bromine onto powdery chitin, chitosan and cellulose was studied in an aqueous bromine-potassium bromide solution at 30°C. Chitosan was found to show an excellent ability of adsorbing bromine as well as iodine. The chitosan film also exhibited high ability of adsorbing bromine both in methanol and in aqueous potassium bromide solutions.     

Structure of coals studied by iodine and water adsorption

Vitrinite in coal is considered as a macromolecular system exhibiting intermolecular microporosity. The surface of this microporosity reflects the structures of the macromolecular system. Adsorption of nitrogen and carbon dioxide provide micropore volumes; adsorption of water and ammonia respond to surface polarity; adsorption of iodine responds to electron availability to form charge transfer complexes. Iodine was adsorbed, both from the vapour phase and aqueous KI solution, by a rank range of coals, fresh, oxidized and pyrolysed. Extents of iodine adsorption were greater from aqueous solution and increased with increasing coal rank to about 87wt% C and then decreased. Extents decreased with increasing severity of oxidation from both vapour and aqueous phases; extents of iodine adsorption increased with increasing heat treatment temperature of coal pyrolysis to decrease subsequently on charring and coking. Results are interpreted in terms of aromaticity of coals, the extent of cross-linkage, and mechanisms of oxidation and pyrolysis.     

Adsorption of aroma chemicals on cotton fabric from aqueous systems

The adsorption of aroma chemicals on cotton fabric was studied relative to the surfactant concentration, surfactant type, water solubility, and fiber morphology. The adsorption increased with increasing surfactant concentration to a maximum near the critical micelle concentration, then decreased with further increases in surfactant concentration. The adsorption also was found to be highly dependent on the fiber surface area and pore structure; dramatic differences were observed between untreated and mercerized cotton fabric and are believed to be due to morphological differences. Cationic and anionic surfactants increased the aroma chemical adsorption, which varied with surfactant type, with cetyltrimethylammonium chloride (CTAC)>sodium dodecyl sulfate (SDS)>H₂O. Water solubility also influenced adsorption; in most cases, adsorption increased with water solubility. In addition, adsorption was also influenced by chemical structure and hydrophobic interactions. The adsorption of aroma chemicals on cotton fabric can be attributed to the aqueous solution being physically held in capillaries and pore structures within the fibular structure of cotton fiber and also to molecular interactions among the aroma chemical molecules, surfactants, and cotton substrate.     

Crosslinking cotton with poly(itaconic acid) and in situ polymerization of itaconic acid: Fabric mechanical strength retention

Polycarboxylic acids have been used as nonformaldehyde durable press finishing agents for cotton fabrics. Previously, we found that itaconic acid (IA) polymerized in situ on cotton fabric and also in an aqueous solution in the presence of a K₂S₂O₈/NaH₂PO₂ initiation system. Both poly(itaconic acid) (PIA) and the polymer formed by in situ polymerization of IA are able to crosslink cotton cellulose, thus imparting wrinkle resistance to cotton. In this research, we compared the performance of the cotton fabric crosslinked by PIA and that crosslinked by in situ polymerization of IA. The fabric treated with PIA and that treated with IA had similar wrinkle recovery angles. The cotton fabric treated with IA, however, lost more tensile strength than that treated with PIA due to cellulose degradation. We determined the magnitude of the fabric tensile strength loss attributed to crosslinking by separating the tensile strength loss due to cellulose degradation from the total tensile strength loss, and found that the tensile strength loss caused by crosslinking for the fabric treated with PIA was significantly higher than that for the fabric treated with IA. This can probably be attributed to more concentrated crosslinkages formed on the near surface of the PIA‐treated cotton fabric. PIA had poorer penetration into the amorphous cellulose region in fiber interior due to its much larger molecular size, thus increasing its concentration on the fabric's near surface. The data also suggest that more concentrated crosslinkages on the fabric surface reduced fabric abrasion resistance. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2023–2030, 2003     

Adsorption behaviors of mercury from aqueous solution using sulfur-impregnated adsorbent developed from coal

Adsorption of mercury from aqueous solution on sulfur-impregnated adsorbent has been studied. Raw coal was mixed with K₂S powder, and then heated at 800-1000 °C for 30 min in nitrogen to produce sulfur-impregnated adsorbent. The sulfur content and specific surface area of the adsorbent were determined, and the ability of the adsorbent to adsorb mercury in aqueous solution was examined. With increasing temperature of sulfur-impregnation, specific surface area of the adsorbent increases, while sulfur content of the adsorbent is almost constant. The adsorbent obtained at 900 °C shows the highest and fastest adsorption of mercury from aqueous solution at 25 °C, and the elution extents of adsorbed mercury are negligible in distilled water and 10% in 0.1 M HCl solution, respectively. Adsorption kinetics was tested for pseudo-first order and pseudo-second order reactions, and the rate constants of adsorption for these kinetic models were calculated. Adsorption experiments demonstrate that the adsorption process corresponds to pseudo-second-order kinetic model than pseudo-first-order model. With increasing temperature of aqueous solution, the kinetics of adsorption becomes faster and the amount of mercury adsorbed on the adsorbent increases. The thermodynamic values, ΔG⁰, ΔH⁰ and ΔS⁰, indicated that adsorption was an endothermic and spontaneous process.     

KOH活化制备高比表面积窄孔径分布的活性炭纤维的研究

以ＫＯＨ溶液浸渍聚丙烯腈系预氧织物为原料,制备了高比表面积窄孔径分布的活性炭纤维,考察了ＫＯＨ浸渍量、活化温度、活化时间等因素的影响,并对活性炭纤维的孔结构及其吸附性能进行了分析。结果表明：ＫＯＨ的浸渍量,活化温度,活化时间都有一最佳值,苯吸附较碘吸附更能反应该活性的吸附性能。     

Adsorption of 2,4-dichlorophenol from Aqueous Solution by a New Low-Cost Adsorbent – Activated Bamboo Charcoal

Adsorption experiments were conducted to study the removal of 2,4-dichlorophenol (2,4-DCP) from aqueous solution by a new low-cost adsorbent-activated bamboo charcoal. The results showed that acidic pH was favorable for the adsorption and removal of 2,4-DCP. Higher initial 2,4-DCP concentrations led to higher adsorption capacity. Most of the adsorption of 2,4-DCP occurred within the first 5 min, and about 90% of 2,4-DCP were removed from solution. After 5 min, the adsorption capacity increased slowly with contact time and the adsorption reached equilibrium in less than 100 min. As the adsorbent dose was increased, the removal of 2,4-DCP was increased, while the equilibrium time was slightly affected. Adsorption kinetics could be best described by the pseudo-second-order model, independent of adsorbent dosages. The adsorption behavior of 2,4-DCP onto bamboo charcoal fitted both Langmuir and Freundlich isotherms well, but followed Freundlich isotherm more precisely. This study demonstrated for the first time that activated bamboo charcoal could be used for the removal of 2,4-DCP in water treatment.     

Iodine adsorption and structure of activated carbons

Studies were conducted on the adsorption of iodine from saturated aqueous solutions and from saturated vapor by eight activated carbons of greatly diverse pore structures. Water adsorption data were used to determine the pore size distribution curves which provided both the distributions of the pore constriction (desorption) and cavity (adsorption) diameters. Adsorption from aqueous phase formed a unimolecular layer on the carbon surface while adsorption from saturated vapor produced pore-filling of micropores (pores less than 30 Å diameter) and surface coverage of the macropores. A great deal of steric interference was present because of the small difference in the diameter of iodine molecule (4.94 Å) relative to the 10–30 Å diameter pores. Good correlation was attained between adsorption and pore structure when corrections were made for the steric effect and the mean diameter distributions of the constrictions and cavities were used. The model for the iodine-on-carbon adsorption resembles packing of spheres into cylinders.     

E.s.r. study of the interactions between a rank range of coals, fresh and oxidized, with iodine

The adsorption of iodine from aqueous solution by coals of different rank was studied. The interaction between coal and iodine was measured by e.s.r. Maximum values for iodine take up were obtained at 87 wt % C (daf) coal by adsorption experiments. The spin concentration ratio between coal and the coal—iodine complex obtained from the e.s.r. experiments also showed a maximum at the same wt % C value. Oxidation of coal decreases its ability to form charge-transfer complexes and this phenomenon may be related to the formation of crosslinks between oxygenated functional groups in coal.     

醋酸可的松合成中碘化反应工艺优化

以21-脱氧可的松(SSC)为原料、溴碘液为碘化剂,研究了SSC转化为一碘化物及一碘化物与二碘化物相互转化的反应过程,考察了摩尔比SSC/I2 (溴碘液)、溴碘液滴加速度、反应时间、反应温度等因素对C-21位碘化反应的影响,以获得一碘化物为目标优化了反应工艺,采用高效液相色谱检测反应体系中一碘化物、二碘化物及SCC的浓度变化。结果表明,SSC转化为一碘化物与一碘化物转化成二碘化物为竞争反应,在溴碘液滴加结束的后续反应过程中二碘化物可以转化为一碘化物。生成一碘化物最多的最佳工艺条件为SSC/I2 (溴碘液)摩尔比1:0.62、溴碘液滴加速度0.33 mL/min (SSC 20 g)、后续保温反应时间120 min、反应温度?3℃。该条件下醋酸可的松的平均摩尔收率为87.67%,比文献提高了14.93%。     

Comparative Study of In situ/Ex situ Activated Trimetallic NiMoW Sulfide Catalysts Prepared from Ammonium Thiomolybdotungstates

Unsupported trimetallic NiMoW sulfide catalysts with high hydro-desulphurization activities are prepared from Ni-containing ammonium thiomolybdo tungstates by in situ and ex situ activation. These precursors are prepared by adding an aqueous NiCl₂ solution to an aqueous (NH₄)₄MoWS₈ solution in either a 1:1 or 0.5:1 Ni/Mo(W) molar ratio. The resulting precursors Ni_0.5/(NH₄)₄MoWS₈ and Ni/(NH₄)₄MoWS₈ yield Ni_0.5MoW-in situ, NiMoW-in situ, Ni_0.5MoW-ex situ and NiMoW-ex situ sulphide catalysts, respectively. The activation method affects both physical and chemical properties, such as macro and microstructure, crystalline structure, specific surface area, N₂ adsorption–desorption isotherms. The in situ/ex situ activation of these ammonium thiotrimetallate precursors leads to a mesoporous structure with a pore size ranging from 20 to 60 Å and type IV N₂ adsorption–desorption isotherms. X-ray diffraction patterns of unsupported NiMoW sulfide catalysts correspond to those of a microcrystalline material, with outstanding reflections attributed to MoS₂, WS₂, NiS, and Ni₉S₈ phases.     

Quaternized Three-Dimensionally Ordered Macroporous Cross-Linked Polystyrene and its Adsorption Character toward Salicylic Acid in Aqueous Solution

Three-dimensionally ordered macroporous cross-linked polystyrene loaded with quaternary ammonium groups (3DOM CLPS-QA) was prepared for using as a novel adsorbent. The performance of 3DOM adsorbent was evaluated by adsorbing salicylic acid (SA) in aqueous solution. Adsorption isotherm and kinetics were investigated under different temperatures (293 K, 303 K, 313 K). The rising temperature led to a significant increase in the adsorption capacity towards SA, and 3DOM CLPS-QA exhibited a high adsorption capacity (317.86 mg/g when the initial concentration of SA was 500 mg/L at 303 K). Moreover, the effect of solution pH on adsorption indicated that the charge interaction was the dominating driving force for the adsorption of SA onto 3DOM CLPS-QA from the aqueous solution. The 3DOM adsorbent was also reusable and could be regenerated by 0.1 M hydrochloric acid solution. After reusing for six times, the adsorption capacity still maintained about 80% of the original capability.     

Bromination of some aromatic compounds by means of bromine in chlorosulphonic acid medium

Bromination of a series of aromatic compounds is carried out by means of bromine in chlorosulphonic acid medium in the presence of iodine as a halogen carrier. Some compounds are brominated and oxidised, the others are brominated only with brominolysis of the groups present, e.g. -CHO, -COOH, -NO₂ and -CN groups.     

A new rapid titration method for determining the halogen ratio of Wijs solution and of iodine monochloride

The free iodine in Wijs solution is titrated directly, in strong hydrochloric acid solution, with standard potassium iodate solution. From this titration and the usual sodium thiosulfate titration for total halogen, the iodine/chlorine ratio is calculated. Results agree closely with those obtained by the longer chlorine-water method of Lopes. The halogen ratio of reagent grade iodine monochloride, a convenient material from which to prepare Wijs reagent directly, is also determined by the new titration method.     

The efficiency of reaction between reactive fluorescent whitening agents and wool

Potential fluorescent whitening agents (FWAs) containing halogen atoms which intramolecularly quench fluorescence have been synthesised and applied to wool in a number of ways. Application by cold pad-batch methods revealed that the complete displacement of all halogen atoms by nucleophilic groups in wool did not take place. Treatment of these materials with morpholine, sodium carbonate or water was necessary to develop the full potential fluorescence yield of the FWA on the fabric. The fluorescence of FWAs can be quenched by the heavy atom effect, as shown by the fact that no fluorescence was observed when commercial FWAs were applied to brominated wool. If the FWA-treated brominated fabrics were subjected to a reduction treatment then the bromine atoms were removed and the fluorescence of the FWA was restored. Application of the potential FWAs by exhaustion, with thioureadioxide present in the liquor, at high temperatures always led to strongly fluorescent fabrics, implying that the halogen atoms were completely displaced using this application method, but the question remains as to how much of the displacement leads to covalent bonds between the fabric and the FWA.     

Flexible Oxygen-Bridged Porous Organic Polymers for Adsorping and Fluorescence Sensing Iodine and the Formation of Liquid Complexes of POPs-(Poly)Iodide Anions

Three flexible oxygen-bridged porous organic polymers (TPG, HCCPA, and HPG) have been synthesized by nucleophilic substitution polymerization reactions. The three POPs display efficient and reversible adsorption of radioactive I₂ in vapor and solution. In iodine vapor at 350 K, the maximum iodine adsorption capacities of TPG, HCCPA, and HPG are 5.29, 4.08, and 1.63 g g⁻¹, respectively. The strong affinities for I₂ are mainly due to the charge transfer of the POPs to iodine. Interestingly, with the decrease of iodine adsorption, charge transfer complexes of TPG, HCCPA, and HPG exhibit liquid, semi-solid, and solid states, respectively. Furthermore, the three POPs have been found to fluorescently detect molecular iodine. The S–V quenching constants of TPG, HCCPA, and HPG are 2.01 × 10⁴, 1.14 × 10⁴, and 1.44 × 10³ L mol⁻¹, respectively. Their sensitivities decrease with the decrease of iodine adsorption. Pleasingly, HCCPA can sense molecular iodine by fluorescence in aqueous solution. Most probably, this is the first example of POPs used for fluorescent sensing molecular iodine in aqueous solution. Both TPG and HCCPA act as efficient adsorbents and chemical sensors of iodine.     

The removal of sodium dodecyl benzene sulfonate by activated carbon modified with quaternary ammonium from aqueous solution

Activated carbon (AC) was modified via grafting quaternary ammonium for the selective adsorption of sodium dodecyl benzene sulfonate (SDBS) from aqueous solution. The surface modification of AC was confirmed by FT-IR, XPS and Raman spectroscopy. The results showed that the modified AC selectively adsorbed the anionic SDBS. Adsorption kinetics could be well described by pseudo-second-order kinetic equation (or three-stage intraparticle diffusion mode), adsorption isotherms fitted well with Langmuir model. Quaternary ammonium on AC enhanced electropositivity and led to the selective adsorption of SDBS.     

Neutron activation analysis as a method for measuring soil removal of unsaturated oils and for estimating their degree of aging on fabric

Neutron activation analysis of bromine-tagged oils on fabric provides a quantitative method for evaluating the degree of aging of unsaturated oils on fabric as well as a new method for measuring their soil removal by estimating the quantity of double bonds, before and after laundering. When aged at 21°C for 5 wk, 62, 63, and 20% of double bonds remained for oleic acid, triolein, and squalene, respectively. At 40°C, no double bonds were left after aging of oleic acid and triolein, whereas about 8% of the double bonds remained for squalene. A comparison of this method with the radiotracer method for soil removal measurements shows good agreement between the two methods. Proper treatment time for bromine tagging of unsaturated oils on fabric is any time between 90 s and 10 min under the bromination procedure used. The tagging of double bonds by bromine vapor has advantages of the exact one-to-one reaction ratio between Br₂ and the number of double bonds of unsaturated oleic acid or triolein, as well as a much lower cost than other tagging reagents like OsO₄. Because blank unsoiled fabric was shown to take up Br₂, fabric swatches of the same size should be used as controls in neutron activation analysis. This method has advantages of its sensitivity to small amounts, use of nonlabeled soil, quantitative measurement, and ease of sample preparation over the chemical measurement of iodine value.