APPLICATION OF MODIFIED POLYACYLAMIDE IN TREATMENT OF PAPERMAKING DEINKING WASTEWATER

In this paper, the application of modified polyacylamide is discussed and the complex systems of PAC/modified PAM are used to treat the papermaking wastewater. The results showed that when cationic polyacylamide (CPAM) and amphoteric polyacylamide (AmPAM) were used at the dosage of 0.75ppm with PAC, of which the optimum dosage was 100ppm, the removed rate of CODcr was above 80% .

THE EFFECT OF TRANSITION METAL IONS-IRON ON HYDROGEN PEROXIDE BLEACHING

Hydrogen peroxide bleaching has been extensivelyused in high-yield pulp bleaching. Unfortunately,hydrogen peroxide can be decomposed underalkaline condition, especially when transition metalions exit. Experiments show that the valence oftransition metal ion is also responsible for thedecomposition of hydrogen peroxide.Iron ions are present in two oxidation states, Fe2+ andFe3+. They are both catalytically active to hydrogenperoxide decomposition. Because Fe3+ is brown, itcan affect the brightness of pulp directly, it can alsocombine with phenol, forming complexes which notonly are stable structures and are difficult to beremoved from pulp, but also significantly affect thebrightness of pulp because of their color.Sodium silicate and magnesium sulfate, when usedtogether, can greatly decrease hydrogen peroxidedecomposition. The optimum dosage of sodiumsilicate is about 0.1% (on solution) for Fe2~ and0.25% (on solution) for Fe3~. Adding chelants such asDTPA or EDTA with stabilizers simultaneously canobviously improve pulp brightness. For iron ions, thechelate effect of DTPA is better than that of EDTA.Under acidic conditions, sodium hyposulfite andcellulose can reduce Fe3+ to Fez+ effectively, and pulpbrightness is improved greatly. Adding sodiumthiosulfate simultaneously with magnesium sulfate,sodium silicate, and DTPA to alkaline peroxidesolution can result in higher brightness of pulp.pH is a key parameter during hydrogen peroxidebleaching, the optimum pH value should be 10.5-12.

THREE-PHASE CIRCULATING FLUIDIZED BED EVAPORATOR FOR WHEAT STRAW BLACK LIQUOR EVAPORATION

A novel vapor-liquid-solid circulating fluidized bed evaporator, meaning for enhancing heat transfer and preventing fouling, is applied to wheat straw black liquor, which is the primary pollutant in China’s papermaking industry. It is treated by alkali recovery, in which evaporation is a key process. The experimental results show that the vapor-liquid-solid three-phase boiling heat transfer coefficient is enhanced by 20%～40% than that of vapor-liquid two-phase boiling flow, also, the novel evaporator exhibits an excellent function of fouling prevention.

RESEARCH ON REUSE OF PAPERMAKING LIGNIN-CONVERSION OF LIGNIN TO BTX BY CATALYTIC PYROLYSIS IN A POWDER PARTICLE FLUIDIZED BED

Experiments on the catalytic pyrolysis of the papermaking lignin were conduced by using a new type of powder-particle fluidized bed to improve the yield of the light aromatic hydrocarbon, i.e. benzene, toluene, xylene and naphthalene (BTXN), in which the primary decomposition and secondary catalytic reaction occur simultaneously at ambient pressure. The effect of catalyst species, fluidizing gases and pyrolysis temperature on the yield of the BTXN were investigated. The content of sulfur is high in the papermaking lignin, and the volatile matter is effected by the temperature. In the case of the inert media silica sand, the yield and the distribution of the pyrolysis products were almost unchanged under the different kind of atmosphere. In the case of the catalyst CoMo-B with hydrogen atmosphere, the intermediate BTXN yield reached 2.52wt%, dry, 3.3 times as much as that in the case of silica sand. Therefore, in order to obtain valuable BTXN as an intermediate in the pyrolysis as much as possible, it is extremely important to select high sulfur resistance and hydrogenization activity catalyst.

STUDY ON THE RETENTION MECHANISMS OF HIGH MOLECULAR WEIGHT CATIONIC POLYACRYLAMIDE

Cationic polyacrylamide (CPAM), used as a retention and drainage aid in paper industry, has received much attention. As the white water system becomes more closed and the anionic trash in the furnish is accumulated, the anionic trash catcher (ATC) is often applied to neutralize the anionic trash. In this paper, we applied colloid titration and Zeta potential analysis to measure the charge and Zeta potential of paper furnish under the conditions of only adding CPAM and adding both CPAM and polyaluminum chloride (PAC). The underlying mechanism was studied.

PREPARATION AND CHARACTERIZATION OF MODIFIED STARCH-BASED BIODEGRADABLE MATERIALS REINFORCED WITH PULP FIBER

Native corn starch and hydroxypropyl starch (HPS) based plastic films were prepared using the short pulp fiber as reinforcement and the glycerol as the plasticizer. The results of tensile test showed that the tensile strength and the elongation at break increased with the pulp contents. With the glycerol contents, the elongation at break increased considerably, but the tensile strength decreased. The water uptake of the films decreased with the pulp contents and hydroxypropylation, but increased with the glycerol contents. So it is concluded that the films was reinforced by pulp fiber and hydroxypropylation.

THE EFFECT OF TRANSITION METAL IONS-MANGANESE ON HYDROGEN PEROXIDE BLEACHING

In this investigation, the catalytic activities of Mn(II),Mn(III) and Mn(IV) towards decomposing hydrogenperoxide were compared. Among Mn (II), Mn (III)and Mn (IV), Mn (II) is not catalytically active indecomposing hydrogen peroxide. However, both Mn(113) and Mn (IV) are, and Mn (III) has a strongereffect than Mn(IV).In addition, we also studied the practical methods todecrease the Mn-induced decomposition of hydrogenperoxide. The results showed that sodium silicate andmagnesium sulfite in combination can effectivelydecrease the decomposition of hydrogen peroxide.The optimum dosage of sodium silicate was about0.5% (on solution). Adding chelants such as DTPAor EDTA simultaneously with stabilizers candecrease hydrogen peroxide decomposition. For Mn(IV), the EDTA is more effective than DTPA.Adding sodium thiosulfate simultaneously withmagnesium sulfate, sodium silicate and DTPA toalkaline peroxide solution can result in more residualhydrogen peroxide, and a higher pulp brightness.

STDUY ON RETENTION AND DRAINAGE PROPERTIES OF THE HIGH SUBSTITUTED DEGREE CATIONIC STARCH

This paper deals with the retention and drainage properties of the high substituted degree cationic starch (HCS) prepared by half-dry process. The experiments show that HCS has remarkable effects on filler retention and drainage in papermaking industry. With the degree of substitution (DS) of HCS increasing, the effects on filler retention and drainage increase. When the DS of HCS is 0.509 and the dosage is 0.08%, the freeness decreases about 12oSR and the filler retention is 79.82%.

STUDY ON THE HEAT TRANSFER PROPERTIES OF BLACK LIQUOR FROM WHEAT PULPING

The heat transfer properties of black liquor from wheat pulp in a stirring apparatus were studied in this paper. By changing the experiment conditions of temperature-difference driving force, geometry shape and agitator speed, we investigated the heat transfer properties of black liquor from wheat pulp under the conditions of different physical properties, rheological properties, fluid power conditions and the space geometrical characteristics of fluid flow. Furthermore the related mathematical models and evaluation criteria based on the conventional methods and artificial neural networks were established. The experimental results showed that the above-mentioned factors have obvious effect to black liquor from wheat pulp?

THE STUDY OF UV-PHOTOCHROMIC ANTI-COUNTERFEIT PAPER

The hydrophilicity, dispersity and minuteness of UV (ultraviolet)-photochromic special function materials and its retention and formation mechanisms in stock were comprehensively studied, and the retention mechanism of UV-photochromic fiber was also studied. In addition, according to the disadvantages of special function materials such as big grain, bad hydrophilicity, expensive price and so on, this paper displays our effects focused on the developing of anti-counterfeit pigments slurry system. Moreover, the properties and anti-counterfeit mechanism of the paper with different special function materials were researched by fluorescent spectrum.

PREPARATION AND APPLICATION OF COPOLYMERS OF 2-ACRYLAMIDO-2-METHYL PROPANE SULFO ACID AS WASTE WATER TREATMENT AGENTS

In this paper, the preparation and application of copolymers of 2-acrylamido-2-methyl propane sulfo acid (AMPS) were discussed. The results showed that the copolymers with molecular weight 18.10 million can be prepared. In treating waste water from deinked pulp, the dosage of copolymers was 0.75ppm, the optimum dosage of PAC was 100ppm; dosage of the amphoteric polyacylamide (AmPAM) with molecular weight 11.34 million was 0.75ppm, the optimum dosage of PAC was 75ppm. The removed rate of CODcr was above 70%.

THE APPLICATION OF CATIONIC POLYACRYLAMIDE AS DRAINAGE AND RETENTION AIDS

Cationic polyacrylamide(CPAM) which was prepared through complex initiation system in laboratory and cationic polyacrylamide(Ciba) were used as retention and drainage aids for bleached wheat straw pulp. The influences of (polydiallyldimethlammonium chloride) PDADMAC and PDADMAC/CPAM on Zeta potential and drainability of pulp was investigated. The dual drainage and retention systems such as CPAM/modified bentonite, CPAM/colloidal SiO2, as well as their comparison between the two systems were discussed, and the optimal dosages of additives were determined. The results showed that: the complex systems can further enhance filler retention, drainability of pulp and strength properties of paper.

PRELIMINARY STUDY ON RETRO-REFLECTIVE COATED PAPER BASED ON MICROGLASS BEADS

High-reflectivity micro-glass bead, as a kind of retro-reflective material, is widely used in reflective fabric or film and other reflective coatings. But it is rarely used in coated paper. The retro-reflective theory of micro-bead is described. Also the effect of size of micro-bead, dosage of binder and different color layers on reflective properties of coated paper are discussed in this article. The results show that its retro-reflective efficiency is good, equally to reflective fabric or film when the micro-glass bead is used in coated paper.

A Report on an ELT Research

Communicative language teaching and audio-lingual teaching approaches have been well recognized in the western cultures as advanced teaching approaches. While in China, we don't get the same teaching effects. Why? The paper reports a research on English language teaching approaches for Chinese non-English majors with 150 sophomores from