Chlorine-based Chemicals Research Articles

Thermal recycling strategy of Coca-Cola PVC label films by its co-carbonization with Terminalia ivorensis leaves

The Coca-Cola company utilizes PVC label films for its product packaging, which may be due to their high physicochemical durability. However, these films are less recycled in comparison with other plastics due to their release of chlorine-based chemicals, leading to environmental pollution on a global scale. In this study, Coca-Cola PVC label films were co-carbonized with Terminalia ivorensis leaves (TIL) in a top-lit updraft reactor to produce biochar. The properties of the PVC-impregnated biochar (TIL-PVC-biochar) were compared with those of the leaves (TIL-biochar), using SEM-EDX, FTIR, BET analysis, and DTA/TGA to study the effect of the PVC on the material. The carbonization process, which ran for duration of 100 minutes, gave a yield of 42.50% and 45.60% for TIL-biochar and TIL-PVC-biochar, respectively. The EDX result confirmed the success of the impregnation process with an increased concentration of carbon and chlorine in TIL-PVC-biochar. The SEM result indicates the presence of good interfacial bonding around the thermo-chemically disintegrated PVC particles. BET analysis showed that PVC impregnation reduced the surface and pore properties of the biochar. TIL-PVC-biochar had a BET surface area and a pore diameter of 194 m 2 /g and 2.088 nm, respectively. FTIR analysis showed TIL-PVC-biochar contained functional groups such as hydroxyl, carbonyl, carboxylic, alkene, and alkyne groups. It also confirmed the presence of chlorine. DTA/TGA showed that TIL-PVC-biochar was more thermally stable than TIL-biochar. The properties of TIL-PVC-biochar make it a good material for the production of conductive composites and an adsorbent for the sequestration of pollutants from the environment.

Improvement of the chlorine resistance of graphene oxide membranes through siloxane cross-linking

ABSTRACT Nanofiltration membranes exhibit performance deterioration when exposed to highly concentrated chlorinated environments. This is a major challenge of nanofiltration process as chlorine-based chemicals are prevalent within industry for the treatment of organic fouling; thus, making membrane chlorine sensitivity detrimental to sustainable operation. Graphene oxide has an inherent chlorine sensitivity and degrades under exposure to high concentration of chlorine. This work describes a novel nanofiltration membrane fabrication strategy in which Polyethyleneimine and siloxane crosslinking chemistries were used to protect the carboxylic, hydroxyl, and epoxy functional groups of GO nanosheets from the attack of free chlorine. These chemistries were used to improve the chlorine-stability of the GO nanosheets. Polyethyleneimine (PEI) reduces GO and cross-links with oxygenated functional groups preventing their further reaction with chlorine. This chemistry was compared to the chlorine-tolerant siloxane cross-linkers which react with GO’s functional groups to decrease reaction sites. The use of (3-Aminopropyl)triethoxysilane (APTES) and (3-Glycidyloxypropyl)trimethoxysilane (GLYMO) cross-linkers resulted in stable retentions that varied by less than 0.5% following 1,000 ppm chlorine exposure for 1 h. Additionally, GLYMO functionalisation of the GO membrane exhibited exceptional chlorine resistance maintaining a methyl blue retention of 98.0 ± 2.15% following 1 h of exposure 30,000 ppm of chlorine.

A thermostable and CBM2-linked GH10 xylanase from Thermobifida fusca for paper bleaching.

Xylanases have the potential to be used as bio-deinking and bio-bleaching materials and their application will decrease the consumption of the chlorine-based chemicals currently used for this purpose. However, xylanases with specific properties could act effectively, such as having significant thermostability and alkali resistance, etc. In this study, we found that TfXyl10A, a xylanase from Thermobifida fusca, was greatly induced to transcript by microcrystalline cellulose (MCC) substrate. Biochemical characterization showed that TfXyl10A is optimally effective at temperature of 80 °C and pH of 9.0. After removing the carbohydrate-binding module (CBM) and linker regions, the optimum temperature of TfXyl10A-CD was reduced by 10°C (to 70°C), at which the enzyme’s temperature tolerance was also weakened. While truncating only the CBM domain (TfXyl10AdC) had no significant effect on its thermostability. Importantly, polysaccharide-binding experiment showed that the auxiliary domain CBM2 could specifically bind to cellulose substrates, which endowed xylanase TfXyl10A with the ability to degrade xylan surrounding cellulose. These results indicated that TfXyl10A might be an excellent candidate in bio-bleaching processes of paper industry. In addition, the features of active-site architecture of TfXyl10A in GH10 family were further analyzed. By mutating each residue at the -2 and -1 subsites to alanine, the binding force and enzyme activity of mutants were observably decreased. Interestingly, the mutant E51A, locating at the distal -3 subsite, exhibited 90% increase in relative activity compared with wild-type (WT) enzyme TfXyl10A-CD (the catalytic domain of TfXyl110A). This study explored the function of a GH10 xylanase containing a CBM2 domain and the contribution of amino acids in active-site architecture to catalytic activity. The results obtained provide guidance for the rational design of xylanases for industrial applications under high heat and alkali-based operating conditions, such as paper bleaching.

Biobleaching: An eco-friendly approach to reduce chemical consumption and pollutants generation

Abstract The pulp and paper industry is known to be a large contributor to environmental pollution due to the huge consumption of chemicals and energy. Several chemicals including H2SO4, Cl2, ClO2, NaOH, and H2O2 are used during the bleaching process. These chemicals react with lignin and carbohydrates to generate a substantial amount of pollutants in bleach effluents. Environmental pressure has compelled the pulp and paper industry to reduce pollutant generation from the bleaching section. Enzymes have emerged as simple, economical, and eco-friendly alternatives for bleaching of pulp. The pretreatment of pulp with enzymes is termed as biobleaching or pre-bleaching. Different microbial enzymes such as xylanases, pectinases, laccases, manganese peroxidases (MnP), and lignin peroxidases are used for biobleaching. Xylanases depolymerize the hemicelluloses precipitated on pulp fiber surfaces and improves the efficiency of bleaching chemicals. Xylanase treatment also increases the pulp fibrillation and reduces the beating time of the pulp. Pectinases hydrolyze pectin available in the pulp fibers and improve the papermaking process. Laccase treatment is found more effective along with mediator molecules (as a laccase-mediator system). Biobleaching of pulp results in the superior quality of pulp along with lower consumption of chlorine-based chemicals and lower generation of adsorbable organic halidesadsorbable organic halides (AOX. An enzyme pretreatment reduces the kappa number of pulp and improves ISO brightness significantly. Better physical strength properties and pulp viscosity have also been observed during biobleaching of pulp.

塩素系薬剤を用いた微生物対策 (第13報）複数の薬剤による微生物抑制効果の検討

塩素系薬剤を用いた微生物対策 (第13報）複数の薬剤による微生物抑制効果の検討

塩素系薬剤を用いた微生物対策 (第1 5 報）枯草菌（芽胞） による殺菌効果の検証

塩素系薬剤を用いた微生物対策 (第1 5 報）枯草菌（芽胞） による殺菌効果の検証

Pollution over Southeast Asia May Threaten Ozone Health

Emissions of short-lived chlorine-based chemicals that deplete ozone are increasing worldwide. But over some regions of Asia, these chemicals may be on a fast track to the ozone layer.

Germany gets boost in chlorine chemistry

AkzoNobel and Vinnolit are both expanding capacity in Germany for chlorine-based chemicals. AkzoNobel recently replaced mercury-cell chlorine production at its site in Frankfurt with more modern membrane technology. The project yielded additional chlorine capacity, which the company will use to expand output of chloromethanes. Vinnolit, the German affiliate of U.S.-based Westlake Chemical, is also installing a membrane chlorine unit, at its Gendorf, Germany, site. The company will use the additional output to expand vinyl chloride capacity. It expects to wrap up the projects by 2021.

D-34 塩素系薬剤を用いた微生物対策 : (第10報) 菌数測定による詳細評価と積算薬剤沈着量の検討

D-34 塩素系薬剤を用いた微生物対策 : (第10報) 菌数測定による詳細評価と積算薬剤沈着量の検討

AkzoNobel to exit chemicals within 12 months

AkzoNobel intends to divest its chemicals business within the next 12 months. The move will return more money to shareholders than would accepting an unsolicited takeover offer from PPG Industries, AkzoNobel’s CEO Ton Buchner told analysts at a London briefing on April 19. AkzoNobel said it will either float shares of its chemicals business on the stock market or sell the business as a whole to another company. Analysts estimate it will fetch between $8 billion and $12 billion. The divestment will create a chemicals business with annual sales of $5.0 billion, pretax profits of $1.0 billion, and about 9,000 employees. The business has five key units: surfactants, ethylene oxide and derivatives, polymer chemicals, chlorine-based chemicals, and bleaching chemicals. The sale will leave AkzoNobel as a paints and coatings company with annual sales of $10.0 billion, pretax profits of $1.2 billion, and about 37,000 employees. A sale or share flotation

Optimization of Bio-based Succinic Acid Production from Hardwood Using the Two Stage pretreatments

The steam explosion-chemical pretreatment is a more effective wood pretreatment technique than the conventional physical pretreatment by accelerating reactions during the pretreatment process. In this paper, two-stage pretreatment processes of hardwood were investigated for its enzymatic hydrolysis and the suc-cinic acid yield form the pretreated solid. The first stage pretreatment was performed under conditions of low severity to optimize the amount of solid recovery. In the second stage pretreatment washed solid ma-terial from the first stage pretreatment step was impregnated again with chemical, alkaline or chlorine-based chemicals, to remove a portion of the lignin, and to make the cellulose more accessible to enzymatic attack. The effects of pretreatment were assessed by enzymatic hydrolysis and fermentation, after the two stage pretreatments, Maximum succinic acid yield, 16.1 g l-1 and 77.5%, was obtained when the two stage pretreatments were performed at steam explosion -3% KOH.

Magnetic ion exchange resin treatment for drinking water production

Italian drinking water treatment plants (DWTP) generally use chlorine-based chemicals to achieve the oxidation/disinfection phases of their treatment trains. The main problem related to the application of such disinfectants consists in the formation of disinfection by-products (DBPs) as a result of the reaction with organic substances in the water. Italian regulations set very strict limits for the maximum concentration of chlorine DBPs and, for many DWTPs, the compliance with such a regulation is difficult. Non-oxidative pre-treatments, able to remove organic substances from the water prior to chlorination, could be a suitable solution to overcome this problem. These treatments could increase the water quality, decrease the oxidant demand and, hence, reduce the formation of DBPs. This paper presents an experimental investigation of ion exchange processes for the dissolved organic carbon (DOC) removal by using MIEX® resin. The process was studied as a pre-treatment on raw river water. The DOC removal efficiency and the effects on downstream processes of the treatment train were evaluated.

Screening of white rot fungi for biobleaching of Acacia oxygen-delignified kraft pulp

To reduce the levels of chlorine-based chemicals in Acacia kraft pulp, we sought to isolate white rot fungus strains that could be used for biobleaching. For this purpose, we collected 600 fungal sources from Indonesia and subjected them to a three-step screening method. The first step involved culturing the strains on Acacia mangium wood powder, guaiacol and agar (WGA) medium. Of the 600 sources, 258 strains grew on WGA medium and generated a red color. The second step revealed that 31 of the 258 strains could degrade extractive-free A. mangium wood powder. The third step examined the ability of the strains to bleach A. mangium oxygen-delignified kraft pulp (A-OKP) under various pH conditions and showed that five strains could biobleach A-OKP at pH 5, 6, and 8. In contrast, the biobleaching abilities of Trametes versicolor and Phanerochaete chrysosporium, which served as standards, were much lower than those of the five new strains, particularly at pH 8. These five strains may be useful for biobleaching of A-OKP.

Effect of Chemical Sanitizers with and without Ultrasonication on Listeria monocytogenes as a Biofilm within Polyvinyl Chloride Drain Pipes

As part of a biofilm in a floor drain, Listeria monocytogenes is exceedingly difficult to eradicate with standard sanitizing protocols. The objective of these studies was to test the use of ultrasonication to break up biofilm architecture and allow chemical sanitizers to contact cells directly. L. monocytogenes biofilms were created in model polyvinyl chloride drain pipes. Chemical sanitizers (quaternary ammonium, peroxide, or chlorine) were applied to the drain pipes with and without a 30-s ultrasonication treatment. Controls using sterile water were included for comparison. L. monocytogenes cells were enumerated from the liquid in the drain and the inside wall surface of the pipe. All chemicals lowered numbers of planktonic cells from 6.6 log CFU/ml in the water control to <100 CFU/ml. Attached cells were also affected by the chemical sanitizers. Approximately 6.0 log CFU/cm2 of the inner wall surface was detected in water control pipes, and ultrasonication did not lower these numbers. With or without ultrasonication, the peroxide-based sanitizer was effective for reducing the numbers of attached L. monocytogenes cells, resulting in approximately 2.0 log CFU/cm2. Both the chlorine- and quaternary ammonium–based sanitizers reduced the number of attached L. monocytogenes cells to a lesser degree, resulting in 4.2 to 4.4 log CFU/cm2. However, addition of ultrasonication improved the performance of both these sanitizers, causing a further reduction to 3.1 and 2.9 CFU/cm2 for quaternary ammonium– and chlorine-based chemicals, respectively. These results indicate that a peroxide-based sanitizer alone can be very effective against biofilm L. monocytogenes in drain pipes, and the addition of ultrasonication can improve the effectiveness of chlorine or quaternary ammonium sanitizers.

과산화수소 발생을 위한 전해셀용 양성자 교환 막의 비교

과산화수소의 발생은 일반적으로 유기 산화제를 포함한 산업적 프로세스의 넓은 분야에 응용된다. 과산화수소는 펄프와 제지 공업의 기계적, 화학적 처리를 위하여 사용되고 염소를 기초로 둔 화학제품에 알칼리 처리로 사용된다. 본 연구에서는 Nafiom과 러시아 양이온 교환막인 MK-40, 제조된 SPEEK막을 가스확산전극이 포함된 과산화수소 발생용 전해 셀에서 비교 실험한다. 다른 양성자 교환막에 효과에 따른 과산화수소 발생의 전기화학적 셀의 전압과 전류 효율, 에너지 소모를 연구한다. There is great interest in the applicability of generated hydrogen peroxide to a variety of industrial processes, usually involving oxidation of organics. Hydrogen peroxide is now employed for the bleaching as well as mechanical and chemical treatment in the pulp and paper industries. It addition, it is considered as an agent to displace the traditional alkaline treatments with chlorine-based chemicals. This paper reports a comparative study of <TEX>$H_2O_2$</TEX> electogeneration on gas-diffusion electrode in divided cell with several <TEX>$Nafion^{(R)}$</TEX> proton-exchange membranes, Russian cation-exchange membrane MK-40 and SPEEK membrane. The influence of different PEMs on electro-chemical cell voltage, current efficiency and energy consumption of hydrogen peroxide generation has been studied.

Chlorinated Pools: Bernard et al. Respond

We are pleased to respond to Eggleston because this offers us the opportunity to respond to some of the criticisms that have been formulated since we originally proposed the pool chlorine hypothesis (Bernard et al. 2003). First, the divergent effects of chlorine [described in our recent study (Bernard et al. 2006)]—when this chemical is used to clean surfaces or to sanitize recreational water—are not inconsistent. Chlorine is a nonspecific biocide, and there are clearly situations in which the beneficial effects of this agent need to be balanced against its possible adverse effects. As we explained in the “Discussion” of our recent articles (Bernard et al. 2006; Nickmilder et al. 2007), exposure conditions are radically different when children live in a house cleaned with bleach compared with when they attend an indoor chlorinated pool. When a house is cleaned with bleach, children are not likely to be exposed to high concentrations of chlorine gas or trichloramine because they are not directly involved in the cleaning tasks. In that situation, the balance for children—but not necessarily for people doing the cleaning—is clearly in favor of the beneficial effects of chlorine from a decreased risk of asthma and respiratory allergy (Bernard et al. 2006; Martyny et al. 2005; Nickmilder et al. 2007). In contrast, when attending an indoor pool, children are directly in contact with the chlorination products that they actively inhale as gases, aerosols, or even water. It can be argued that the time children spend in a swimming pool is limited, but we should not forget that chlorine-based chemicals are rapidly acting oxidants, a property essential to their efficacy. Eggleston raises the issue of a possible confounding between age and lifetime cumulative pool attendance (CPA). However, because our study (Bernard et al. 2006) focused on children in 5th and 6th grades, there is little variation in age (range 10–13 years), explaining why age did not emerge as a predictor of the outcomes (Table 1) and also why it did not vary across CPA categories (analysis of variance, p = 0.35). Eggleston states that cases of asthma cannot be allocated to the CPA categories of our Figure 1, but this is because he has misinterpreted the way these categories were constructed. Subjects were not divided into quartiles but into predefined categories of increasing CPA. If numbers of subjects included in each category approximate those of quartiles, this is no more the case when each category is further divided according to the total serum IgE. The reason for this is given in Figure 3, which shows that the proportion of children with higher serum IgE gradually decreases as CPA increases. We agree with Eggleston that the exhaled nitric oxide (eNO) test is not a specific measure of airways inflammation in asthma. Rhinitis is a potential confounder that we took into account by adjusting the odds ratios (ORs) for the sensitization to aeroallergens, including house dust mites, the most frequent allergen in allergic rhinitis. We did not retain medication for asthma or allergy in the final analysis because of the strong collinearity of this factor with some outcomes, such as doctor-diagnosed asthma. However, adding medication to the list of possible predictors did not abolish the association between eNO and CPA (OR, 1.32; 95% confidence interval, 1.09–1.60). We also found no confounding by viral infections, which is not surprising because children seriously affected by a respiratory illness were absent from schools at the time of examination. We used objective measures whenever possible in our study (Bernard et al. 2006), but in order to derive predictors such as CPA, we had no choice but to use the information provided by parents and school directors (for compulsory pool attendance at school). We believe that the strong associations found in our study should not be dismissed as having arisen by bias or insufficient adjustment. However, what makes us increasingly confident in our observations is their reproducibility. The findings reported in our study (Bernard et al. 2006) confirm earlier observations (Bernard et al. 2003), and a new larger study on adolescents, just completed, again brings to light quite strong associations between different indicators of asthma and CPA, especially among atopic children (Bernard et al., unpublished data).

Materials for High-Temperature and High-Pressure Hydrogen Peroxide Bleaching Equipment

Abstract To determine the suitability of grade 705 zirconium (UNS R60705) as a candidate material of construction for high-temperature and pressure hydrogen peroxide (PHT) pulp-bleaching reactors, a series of electrochemical experiments were carried out in simulated PHT environments. Because the PHT process may be incorporated into a closed cycle mill or a mill that also uses chlorine-based chemicals to bleach pulp, the effect of chloride ion concentration on the corrosion of zirconium in PHT environments was studied. It was found that at the potential measured in PHT environments, zirconium was passive (−100 mV vs saturated calomel electrode [SCE]). Breakdown potentials of ≈ 500 mVSCE were measured in chloride-containing solutions. However, when the chloride ion concentration was increased > 50 ppm, the repassivation potential of the zirconium was reduced significantly. Based on these results, grade 705 zirconium was determined to be suitable for a wide range of PHT process conditions.

Microbial removal of chlorinated phenols during aerobic treatment of effluents from radiata pine kraft pulps bleached with chlorine-based chemicals, with or without hemicellulases.

The removal of chlorophenolic compounds from kraft mill effluents bleached with chlorine (cBKME) or chlorine plus hemicellulases (bBKME) was studied in reactors of aerobic treatment lagoons. In these laboratory models, a stable microbial population removed biochemical oxygen demand at similar rates of the mill lagoon. Complete removal of nine chlorophenols and chloroguaiacols during microbial treatment of these effluents was detected by gas chromatography. Abiotic removal was only observed with 2,4-dichlorophenol and 2,4,5-trichlorophenol. There were no significant differences in degradative ability between microorganisms acclimated to grow in reactors fed with cBKME or bBKME. The latter had a lower content of adsorbable organic halogen and chlorophenols than cBKME. Microorganisms acclimated to cBKME or bBKME were only able to grow on phenol or guaiacol as sole carbon source. However, these microorganisms removed (0.1-0.5 mM) 4-chlorophenol, 2,4-dichlorophenol and 2,4-dichlorophenoxyacetate with BKME as primary carbon source. Under these conditions, 2,4,6- and 2,4,5-trichlorophenol, 4,5-dichloroguaiacol, 4,5,6-trichloroguaiacol and tetrachloroguaiacol were not removed. These results suggest that the microbial removal of bleaching chlorophenols and chloroguaiacols during aerobic treatment, probably takes place only because of their very low concentration (1-200 ppb) in BKME.

Back-country water treatment to prevent giardiasis.

This study was conducted to provide current information on the effectiveness of water treatment chemicals and filters for control of Giardia cysts in areas where treated water is not available. Four filters and seven chemical treatments were evaluated for both clear and turbid water at 10 degrees C. Three contact disinfection devices were also tested for cyst inactivation. Filters were tested with 1-liter volumes of water seeded with 3 x 10(4) cysts of G. lamblia produced in gerbils inoculated with in vitro cultured trophozoites; the entire volume of filtrate was examined for cyst passage. Chemical treatments were evaluated at concentrations specified by the manufacturer and for contact times that might be expected of hikers (30 minutes) and campers (eight hours, i.e., overnight). Two of the four filter devices tested were 100 percent effective for Giardia cyst removal. Of the other two filters, one was 90 percent effective and the other considerably less effective. Among the seven disinfection treatments, the iodine-based chemicals were all significantly more effective than the chlorine-based chemicals. None of the chemical treatments achieved 99.9 percent cyst inactivation with only 30-minute contact. After an eight-hour contact each of the iodine but none of the chlorine preparations achieved at least 99.9 percent cyst inactivation. None of the contact disinfection devices provided appreciable cyst inactivation. Heating water to at least 70 degrees C for 10 minutes was an acceptable alternative treatment.

Evaluation of the direct epifluorescent filter technique for assessing the hygienic condition of milking equipment.

The hygienic condition of 6 milking installations, 3 sanitized by circulation cleaning (CC) with chlorine-based chemicals and 3 by flushing with acidified boiling water (ABW), was tested using rinses of quarter strength Ringer's solution. The bacterial content of the rinses was determined using both colony counts and the direct epifluorescent filter technique (DEFT). A comparison of testing methods gave correlation coefficients between colony count and DEFT of 0.82 for plants using CC and 0.46 for plants using ABW. Five strains of bacteria belonging to different genera and commonly found on milking equipment were exposed to various degrees of heat and to various concentrations of chlorine. The effects of such treatments on the staining characteristics of the organisms were studied. It was observed that Staphylococcus aureus and Streptococcus lactis, although killed by heat treatment, stained a bright orange when treated with acridine orange dye. Pseudomonas fluorescens, Escherichia coli and vegetative cells of Bacillus cereus did not take up the orange stain after heat treatment, nor did any of the 5 strains stain orange after treatment with NaOCl. It is suggested that the DEFT is a useful and rapid means of counting bacteria in rinses of equipment where sterilization is due primarily to chlorination, but in the absence of a stain which can differentiate more accurately between dead and living organisms its use is limited where sterilization is carried out solely by heat.