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Abstract: A thermochemical method was performed to enhance lead adsorption of unbleached newspaper pulp. Unbleached pulp was obtained after mechanical treatment of waste newspaper and was chemically modified with citric acid (CA) at 90°C for 90min. The parameters under investigation were the pH of adsorption solution (3–9), the concentration of mechanically and chemically treated pulps (0.1–1g), the concentration of CA (0.5M and 1M), the initial concentration of lead (20–1000mg/l) and the pulp-lead solution contact time (0–24h). The maximum adsorption capacity of mechanically treated newspaper pulp (MT-pulp) increased by 35% (25.71mg/g) after modification with 0.5M CA and 82% (34.6mg/g) with 1M CA. The modification process resulted in higher negative values of zeta potential and surface charge of mechanically treated pulp reaching the highest charge and maximum lead adsorption at pH=6. The adsorption experimental data fitted well to the Langmuir isotherm model and inferred that adsorption and ion-exchange are major mechanisms for binding Pb2+ ions. Kinetic studies for three different concentrations of Pb2+ showed that the adsorption process involved two stages and the experimental data followed the pseudo-second order model. The results showed that CA-modified newspaper pulp is an effective adsorbent for the removal of Pb2+ from wastewater. [Copyright &y& Elsevier]

Abstract: This study examines and quantifies the effect of cationic polyacrylamide (CPAM) dissolution kinetics and charge density on the adsorption and aggregation state of gold nanoparticles (AuNPs) on paper and the resulting Surface Enhanced Raman Scattering (SERS) performance. Dissolution kinetics of CPAM of different charge density was studied by monitoring their viscosity and hydrodynamic diameter over regular intervals of time. It was found that the degree of dissolution of CPAM greatly affected the surface coverage and aggregation of AuNPs on the CPAM pre-adsorbed paper substrate and their SERS reproducibility. CPAM of higher charge density dissolves faster and produced a more uniform aggregation and higher surface coverage of AuNPs on paper for a higher and more reproducible Raman EF. Understanding the CPAM dissolution process enables the optimization of SERS performance of the AuNPs-paper as a bio-diagnostic platform. [Copyright &y& Elsevier]

Abstract: The reaction kinetics of alkaline phosphatase (ALP) adsorbed on paper was quantified by image analysis using a colorimetric technique under conditions of excess enzyme. A classical reaction kinetics approach integrated with image processing technique was used to analyse the coloured product formation from the enzyme substrate reaction against time. The order of reaction and rate constant of enzyme activities on paper surface were calculated. ALP was either physisorbed directly on paper or adsorbed on paper treated with a monolayer of a high molecular weight cationic polyacrylamide (CPAM), an anionic polyacrylic acid (PAA) or a high molecular weight polyethylene oxide (PEO). The reaction rate of enzymatic paper follows a first order reaction with respect to the concentration of enzyme–substrate complex. ALP immobilized on paper has a reaction rate 2 to 3 orders of magnitude lower than the free ALP enzyme in buffer solution. This might be due to a critical loss of enzyme flexibility upon adsorption. No increase in reaction rate was achieved by immobilizing ALP on paper treated with a high molecular weight cationic polyacrylamide (CPAM) or a highly charged anionic polyacrylic acid oligomer (PAA), which suggests the enzyme orientation was not significantly affected. However, the reaction rate for ALP on PEO treated paper was lower than that on CPAM or PAA treated papers. That is probably due to some PEO-enzyme interaction affecting the tertiary structure of the ALP enzyme. [Copyright &y& Elsevier]

Abstract: In the present study the interactions between the main constituents of the refuse derived fuel (plastics, paper, and wood) during pyrolysis were studied. Binary mixtures of polyethylene-paper and polyethylene/sawdust have been transformed into pellets and pyrolyzed. Various mixtures with different composition were analyzed and pyrolysis products (tar, gas, and char) were collected. The mixtures of wood/PE and paper/PE have a different behavior. The wood/PE mixtures showed a much reduced interaction of the various compounds because the yields of pyrolysis products of the mixture can be predicted as linear combination of those of the pure components. On the contrary, a strong char yield increase was found at a low heating rate for paper/PE mixtures. In order to explain the results, the ability of wood and paper char to adsorb and convert the products of PE pyrolysis into was studied. Adsorption and desorption tests were performed on the char obtained by paper and wood by using n-hexadecane as a model compound for the heavy products of PE pyrolysis. [Copyright &y& Elsevier]

Abstract: A papermaking technique with a dual polyelectrolyte retention system was used for the preparation of NaY zeolite-containing papers, which implied the use of cationic and anionic polymers. Two kinds of fibers were employed, either cellulosic or ceramic ones, and accordingly papers with different characteristics were obtained: those that only contained cellulosic fibers for low temperature applications, cellulosic papers, and those prepared using both cellulosic and ceramic fibers – ceramic papers – for high temperature applications. Although a decrease in their mechanical properties due to calcination was observed, zeolitic ceramic papers resulted easy to handle for practical applications. Zeolite was quantified through BET surface area measurements. SEM images indicated a good dispersion of zeolite particles within the cellulosic paper whereas in the ceramic paper they appeared anchored on ceramic fibers. The zeolitic papers prepared resulted efficient as toluene sorbents, the adsorption capacities of zeolitic ceramic papers being higher than those of zeolitic cellulosic papers. In the case of zeolitic cellulosic papers, the amounts of released toluene were lower than those of adsorbed toluene, implying that the treatment up to 160°C did not completely eliminate the hydrocarbon. Also, TPD profiles showed that toluene is chemically retained up to high temperatures (ca. 420°C) in zeolitic ceramic papers. Toluene adsorption values demonstrate that zeolite dispersed into the cellulose/ceramic matrix is as effective as powder massive zeolite in retaining the hydrocarbon, which highlights the potential application of these zeolitic structures as sorbent materials both for low and high temperatures. [Copyright &y& Elsevier]

Abstract: This review paper investigates the synthesis of porous structures with controlled hole pattern and provides an overall view of the various factors involved when synthesizing such porous materials. The following factors are discussed: 1) various methods of synthesis to produce the porous structures; 2) materials which the porous structures are made of; 3) control of the pore structure; 4) various applications of such porous materials. The materials of the porous structures and the control of the pore structure will also be discussed separately under each different method, as these two factors are closely dependent on the method of fabrication. [Copyright &y& Elsevier]

Polymeric carrier fabrics are commonly used in many industrial processes including manufacture of paper and board. Apart from acting as a carrier for the compressible porous material during the manufacturing process, the synthetic woven fabrics comprising mainly of poly ethylene terypthalate (PET) yarns, impart valuable product attributes, i.e. softness, bulk, absorbency, etc. in consumer products. The three-dimensional structure of the fabrics plays a critical role in deciding the manufacturing and energy efficiency as well as product end-use properties.X-ray micro computed tomography (X-μCT) provides a non-intrusive technique to visualize and analyze the three-dimensional structure of porous materials such as paper [The 3 Dimensional Structure of Paper and Its Relationship to Liquid and Vapor Transport, The Science of Papermaking, p. 1289; Tappi J 84 (2001) 1; APPITA 55 (2002) 230]. In this paper, we use this technique to visualize the three-dimensional structure of polymeric fabrics commonly used in paper manufacture [The 3 Dimensional Structure of Paper and Its Relationship to Liquid and Vapor Transport, The Science of Papermaking, p. 1289; Tappi J. 84 (2001) 1; APPITA 55 (2002) 230]. Digital image analysis techniques based on mathematical morphology and stereology were used to determine traditional pore descriptors such as porosity, yarn–void interfacial area, tortuosity and hydraulic radii distribution in the two principal orthogonal directions [The 3 Dimensional Structure of Paper and Its Relationship to Liquid and Vapor Transport, The Science of Papermaking, p. 1289; APPITA 55 (2002) 230]. Comparison of the average yarn diameter by X-μCT and image analysis and physical measurement using light microscopy agreed to within 3% indicating the good accuracy of the X-ray technique. The differences in fabric pore structural characteristics between the in-plane and transverse directions reported here help explain the differences in liquid and vapor transport in the two principal directions.Lattice-Boltzmann simulations of fluid flow and Monte-Carlo simulations of vapor diffusion through actual 3D structures of fabric provide a direct method to predict the permeability and diffusivity characteristics of these complex media. Comparison of structural characteristics between image analysis and simulations show reasonable agreement. [Copyright &y& Elsevier]

Abstract: A rapid non-destructive sampling technique for the analysis of volatile organic compounds (VOCs) emitted by paper sheets is described. A capillary, which is connected to a microcolumn packed with Tenax TA, is inserted between two sheets at the centre of a paper stack encapsulated inside a PET/Al/PE composite foil. The other end of the microcolumn is connected to a gas-tight syringe and an appropriate volume of gaseous phase is aspirated. The microcolumn is then thermally desorbed in a modified GC inlet (modification is presented) and analysed by gas chromatography–mass spectrometry (GC–MS). In the chromatogram from the analysis of artificially aged paper sample 21 compounds were identified. Advantages of the method including the short sampling time (1min), simplicity and economic aspect are discussed. [Copyright &y& Elsevier]