The Life-Cycle of Chlorine, Part I: Chlorine Production and the Chlorine-Mercury Connection

Chlorine is an important industrial chemical. Not only is it a component of many important products, it is also needed for many chemical manufacturing processes, even where it does not appear in the final product. But a number of chlorine chemicals, especially organochlorines, are toxic, carcinogenic, tentogenic or otherwise potentially disturbing to the environment. For this reason, some environmentalists—notably Greenpeace-have advocated a ban, not just on some products but on all uses of elemental chlorine. The chemical industry is taking this threat seriously and mounting a vigorous defense. But the debate so far is not illuminating the issues effectively, because both sides are selectively using questionable and unverifiable data.
The scientific uncertainties are not really the problem. Rather, data in the public domain and accessible to environmentalists and even regulatory authorities are of very poor qualrty. Because of industry secrecy much crucial inforrnation is unavailable and some of what is available is misleading or wrong. The dual purposes of this article, and the ones that follow, are (I) to elucidate the information requirements for an adequate life-cycle analysis of chlorine and its uses and (2) to indicate how and where the use of massbalance methodology can help identify errors and fill in gaps.
The present article deals with electrolytic chlorine produdion and mercury flows arising from chlorine production. Subsequent articles deal with conversion processes and losses and further chemical industry uses of chlorine, major end uses of chlorine and chlorine chemicals, and persistent organochlorine pollutants.     

Effect of Algicidal Quaternaries on the Germicidal Activity of Chlorine on Swimming Pool Water

The Swimming Pool Water Disinfectant Test Method of the Association of Official Analytical Chemists was used to determine the effect of the accepted level of 2 ppm of some commercial quaternary ammonium algicides on the germicidal activity of chlorine. Accurate determinations on the amounts of residual available chlorine in chlorine-quaternary mixtures could not be made by the usual chemical methods. This made it necessary to base all comparisons on the starting concentrations of available chlorine rather than the final concentration as specified in the method employed. No evidence was obtained to support the use of lower concentrations of residual available chlorine for disinfection in the presence of algicidal quaternaries than those commonly recognized as effective by the American Public Health Association. The rate of kill against the gram-positive test organism Streptococcus faecalis was faster in quaternary-chlorine mixtures than in the sodium hypochlorite control solutions. The practical significance of this result in the bench method identified cannot be ascertained in the absence of more sensitive and precise chemical procedures for determining concentrations of residual available chlorine in the presence of quaternaries or in actual swimming pool tests.     

Kinetics and Mechanism of Bacterial Disinfection by Chlorine Dioxide

Survival data are presented for a fecal strain of Escherichia coli exposed to three concentrations of chlorine dioxide at four temperatures. Chick's first-order reaction equation is generalized to a pseudo nth-order model. Nonlinear least squares curve-fitting of the survival data to the nth order model was performed on an analogue computer. The data were observed to follow fractional order kinetics with respect to survival concentration, with an apparent activation energy of 12,000 cal/mole. Initial experiments support the thesis that the mechanism of chlorine dioxide kill occurs via disruption of protein synthesis.     

The Life-Cycle of Chlorine, Part IV

Some cyclic organo-chlorines share key characteristics to a significant degree, notably volatility, solubility in lipids, environmental persistence, a tendency to bioaccumulation, and toxicity to animals. A subset of this group has been designated "persistent organic pollutants" (POPs). Because of their volatility, persistence, and tendency to bioaccumulate, POPs are found in remote locations, such as the Arctic, far from the locations where they were initially used or produced.
Except PCDDs (dioxins) and PCDFs (furans), all are, or were, originally produced for use as such , mainly as pesticides or herbicides. PCDDs and PCDFs have never been produced for their own sake; they are unwanted contaminants of chemical intermediates that were passed on and incorporated in final products, notably herbicides; they are also generated spontaneously in most combustion processes and chlorine bleaching of paper. Most POPs have been sharply restricted or banned outright in most of the industrialized countries, but not in less developed countries.
The qualities of persistence and bioaccumulation give special urgency to monitoring not only point source emissions and local concentrations, but also the mobile environmental reservoirs and exposure routes of these chemicals. To conduct adequate risk analyses, far more detailed data is needed on quantities produced and used, quantities and location of storage, mode of use, location of use, and period of use. Such data are not collected consistently by government or international agencies.     

The effects of physical parameters on laser-induced breakdown spectroscopy analysis of intact tablets

With the advent of the Food and Drug Administration initiatives to investigate and encourage the use of process analytical technologies, laser-induced breakdown spectroscopy (LIBS) is considered an excellent analytical tool to understand the processability of solid dosage form. In this article, the feasibility of the LIBS system for quantitation of active drug within a solid dosage form, as well as the effects of various physical parameters on its signal, is investigated. A model drug containing chlorine and sulfur was used. The examination of the specificity and reproducibility of the measurements led to the use of chlorine and carbon as the internal standard. An overall relative SD of 1.1% for the signal was found. For quantitation purposes, calibration curves using compound-X in formulated tablets were generated. It was found that curves generated from roller-compaction tablets generally gave higher LIBS signal than those generated using direct-compressed (DC) process. To investigate these differences, effect of LIBS signals from several physical properties of the tablets were examined. It was found that unmilled compound-X used in the manufacture of the tablets gave a LIBS signal 30% lower than when milled compound-X was used. However, by using multiple crushing-recompression DC process of the milled compound-X, the LIBS results were comparable with those found from both processed tablets using milled compound-X. Other physical parameters, such as wide ranges of granule size and tablet hardness found in the typical manufacturing process, had limited effect on the LIBS signal. From these results, it was noted that for accurate quantitation, it is necessary to use the same physical properties of compound-X and the same manufacturing process in the calibration standards as the actual samples.     

Chlorine Dioxide Disinfection Temperature Effects

S ummary . Washed suspensions of Escherichia coli were exposed to different concentrations of chlorine dioxide at various temperatures. Platings of the mixtures to evaluate the numbers of surviving cells were made after 5–300 sec of contact. Survival data were best fitted by a reaction model that is first order with respect to cell concentration and to exposure time. Bactericidal rates were found to increase markedly with both increased disinfectant concentrations and increased temperatures. Activation energies at each concentration of chlorine dioxide are reported.     

Kinetics of Atomic Recombination on Silicon Samples in Chlorine Plasma

The recombination kinetics of chlorine atoms on the wall of a plasmachemical reactor and on silicon samples in the positive column of a glow discharge in Cl₂ has been studied experimentally. The rate constants and probabilities of the heterogeneous recombination of chlorine atoms on the plasma limiting surfaces, as well as of the chemical interaction of chlorine atoms with silicon, are calculated. The temperature and time dependences of the probabilities of the chemical interaction of chlorine atoms with silicon are analyzed, and optimal conditions for conducting pulse relaxation experiments are determined.     

Comparison of the Efficacy of Free Residual Chlorine and Monochloramine against Biofilms in Model and Full Scale Cooling Towers

The presence of microbial cells on surfaces results in the formation of biofilms, which may also give rise to microbiologically influenced corrosion. Biofilms accumulate on all submerged industrial and environmental surfaces. The efficacy of disinfectants is usually evaluated using planktonic cultures, which often leads to an underestimate of the concentration required to control a biofilm. The aim of this study was to investigate the efficacy of monochloramine on biofilms developed in a cooling tower. The disinfectants selected for the study were commercial formulations recommended for controlling microbial growth in cooling towers. A cooling tower and a laboratory model recirculating water system were used as biofilm reactors. Although previous studies have evaluated the efficacy of free chlorine and monochloramine for controlling biofilm growth, there is a lack of published data concerning the use monochloramine in cooling towers. Stainless steel coupons were inserted in each tower basin for a period of 30 d before removal. Monochloramine and free chlorine were tested under identical conditions on mixed biofilms which had been allowed to grow on coupons. Monochloramine was found to be significantly more effective than free chlorine against cooling tower biofilms.     

The Life Cycle of Chlorine, Part II: Conversion Processes and Use in the European Chemical Industry

The major purpose of this article is to construct a plausible emissions profile for the European chemical industry from process data and mass balance considerations.' In it we describe this industry and its major conversion processes and emissions. Four major process chains, beginning with methane, ethylene, propylene, and benzene are analyzed, along with five important stand-alone processes. A self-consistent version of the industry is constructed for 1992, based on data from a variety of sources.
In 1992 Europe consumed 9,297 metric kilotons as measured by weight of chlorine (kMT[CI]) of salt and 2 I I kMT(CI) of recycled hydrochloric acid (HCI) to produce 86 I0 kMT of virgin elemental chlorine, plus 278 kMT(CI) of virgin by-product HCI. Total chlorine input to the industry was 8,689 kMT including I2 kMT(CI) of recycled chlorinated hydrocarbons (CHCs) and (net) 79 kMT(CI) of HCI. Shipments of chlorine and HCI to other sectors was 1,367 kMT(CI), while 7,322 kMT(CI) was embodied in products or lost within the sector: Of this subtotal, 350 kMT(CI) was used to manufacture identified inorganic chemicals, 5,694 kMT(CI) for identified organic chemicals, and 1,278 kMT(CI) for "other unspecified" chemicals.
We estimate that products account for 41.6% of inputs (measured at the "fence"), while wastes account for 24.7%     

Chlorine in the Netherlands, Part II: Risk Management in Uncertainty for Chlorine

The debate over chlorine in industrialized economies has become extremely polarized in the last decade. Environmental pressure groups are striving for a virtual phaseout of chlorine and chlorinated hydrocarbons (CHCs), because they are convinced that the risks cannot be managed. Industry argues this is not necessary because environmental risks can be controlled, nor is it feasible, because at least 60% of all firms use CHCs, produds made with CHCs, or elemental chlorine. In an attempt to give this discussion a more factual basis, the Dutch minister of environment launched a strategic study on chlorine (see Kleijn et al. I997;Tukker et al. 1995). Using all available knowledge about emissions and contemporary evaluation methods, the study found only a limited number of environmental issues outstanding related to the chlorine chain: however, it also found important uncertainties. This article describes the outstanding uncertainties in more detail. It defines which uncertainties have to be regarded as chlorine-specific and the extent to which additional research can resolve them. For the remaining uncertainties the potential benefts of uncertainty reduction strategies are evaluted, relying mainly on the precautionary principle     

Toward Sustainable Nanoproducts

Sustainable development of nanotechnology will inevitably require incorporation of life cycle thinking to analyze environmental impacts of nanomanufacturing. While many concerns have been raised regarding the human and ecological health effects of and benefits from using nanoproducts, relatively little attention has been given to the manufacturing phase. Unlike many conventional manufacturing techniques, nanomanufacturing techniques require unique facility and process design as well as operation and control. Accordingly, the environmental burden of most nanomanufacturing techniques may be more profound than that of many other conventional techniques. This article reports on a comprehensive review of the current state of technologies used in the manufacture of nanostructured materials in order to identify those attributes that contribute to environmental impacts. It provides a preliminary analysis of significant attributes of commonly used nanomanufacturing techniques, including strict material purity requirements, less tolerance for defects, low process yields and material utilization efficiencies, repetitive processing steps, the need for specialized environments (such as high temperatures or cryogenic processing), the use of toxic chemicals and solvents, the need for moderate to high vacuum, the use or generation of greenhouse gases, high energy and water consumption, and the potential for chemical exposure.     

Potentiometry of the Reaction of Residual Lignin of Lignocellulose Powder Material with Chlorine Dioxide

The consumption rate of chlorine dioxide in the reaction with the residual lignin was studied using measurements of the potential of a redox couple ClO₂/ClO ₂ ^? in an aqueous suspension of lignocellulose powder material. The methodology was developed for the study of reaction kinetics of chlorine dioxide with the residual lignin using the first order reaction model with the initial lignin concentration in the reaction medium varying in the range of (1–17) × 10^–4 М at the initial chlorine dioxide concentration of 4.48 × 10^–4 М. The monochronic rate constant of the second order reaction of chlorine dioxide with the residual lignin was calculated by the dependence k_eff(I) = k_eff(II)[L]₀ under the lignin excess conditions, it was 1462 ± 108 М^–1 s^–1. Considering the initial concentrations of reagents, it was found that, with increasing the degree of lignin conversion Θ from ≈0.27 to 0.54, its reactivity in the interaction with the chlorine dioxide is reduced, and the value of k_eff(II) decreased from ≈1280 to 900 М^–1 s^–1, which according to the theory of polychronic kinetics was a manifestation of the kinetic nonequivalence of the various ensembles of macromolecules of the residual lignin. Thus, it was experimentally shown for the first time that residual lignin of lignocellulose powder material had a kinetic nonequivalence in the interaction with chlorine dioxide.     

Comparison of Chlorine, Bromine, and Iodine as Disinfectants for Swimming Pool Water

Studies on the germicidal activity of chlorine, bromine, and iodine were made by use of the Association of Official Agricultural Chemists official first action method for determining effectiveness of swimming pool water disinfectants. In this procedure, 0.3 ppm of available chlorine as chlorine gas has activity equivalent to 0.6 ppm of available chlorine in the buffered sodium hypochlorite control when Escherichia coli is used as the test organism. With Streptococcus faecalis as the test organism, 0.45 ppm of available chlorine as gaseous chlorine gives activity equivalent to the control. Liquid bromine at 1.0 ppm is as effective as the 0.6 ppm of available chlorine hypochlorite control with E. coli as the test organism, but 2.0 ppm of liquid bromine is necessary to provide activity equivalent to the 0.6 ppm of available chlorine control when S. faecalis is employed. With iodine as metallic iodine, 2.0 ppm is necessary to provide a result equivalent to the 0.6 ppm of available chlorine control with both E. coli and S. faecalis. In the various systems tested, gaseous chlorine was the most active form of available chlorine; liquid bromine provided the most active form of bromine, and metallic iodine provided the most active form of iodine.     

Influence of Stabilizer Concentration on Effectiveness of Chlorine as an Algicide

Cyanuric acid, used as chlorine stabilizer in swimming pool waters, has a relatively minor effect on the algicidal efficiency of free chlorine. The toxicity of free chlorine to three swimming pool algae was reduced slightly by 25 mg of cyanuric acid per liter if inhibiting, but less than algicidal, concentrations of chlorine were employed. Higher stabilizer concentrations (50, 100, and 200 mg/liter) generally resulted in no further reduction in the algicidal efficiency of free chlorine beyond that observed at 25 mg/liter.     

A simplified techno-economic model for the molecular pharming of antibodies

By the end of 2017, the Food and Drug Administration had approved a total of 77 therapeutic monoclonal antibodies (mAbs), most of which are still manufactured today. Furthermore, global sales of mAbs topped $90 billion in 2017 and are projected to reach $125 billion by 2020. The mAbs approved for human therapy are mostly produced using Chinese hamster ovary (CHO) cells, which require expensive infrastructure for production and purification. Molecular pharming in plants is an alternative approach with the benefits of lower costs, greater scalability, and intrinsic safety. For some platforms, the production cycle is also much quicker. But do these advantages really stack up in economic terms? Earlier techno-economic evaluations have focused on specific platforms or processes and have used different methods, making direct comparisons challenging and the overall benefits of molecular pharming difficult to gauge. Here, we present a simplified techno-economic model for the manufacturing of mAbs, which can be applied to any production platform by focusing on the most important factors that determine the efficiency and cost of bulk drug manufacturing. This model develops economic concepts to identify variables that can be used to achieve cost savings by simultaneously modeling the dynamic costs of upstream production at different scales and the corresponding downstream processing costs for different manufacturing modes (sequential, serial, and continuous). The use of simplified models will help to achieve meaningful comparisons between diverse manufacturing technologies.     

A Spore Counting Method and Cell Culture Model for Chlorine Disinfection Studies of Encephalitozoon syn. Septata intestinalis

The microsporidia have recently been recognized as a group of pathogens that have potential for waterborne transmission; however, little is known about the effects of routine disinfection on microsporidian spore viability. In this study, in vitro growth of Encephalitozoon syn. Septata intestinalis, a microsporidium found in the human gut, was used as a model to assess the effect of chlorine on the infectivity and viability of microsporidian spores. Spore inoculum concentrations were determined by using spectrophotometric measurements (percent transmittance at 625 nm) and by traditional hemacytometer counting. To determine quantitative dose-response data for spore infectivity, we optimized a rabbit kidney cell culture system in 24-well plates, which facilitated calculation of a 50% tissue culture infective dose (TCID₅₀) and a minimal infective dose (MID) for E. intestinalis. The TCID₅₀ is a quantitative measure of infectivity and growth and is the number of organisms that must be present to infect 50% of the cell culture wells tested. The MID is as a measure of a system's permissiveness to infection and a measure of spore infectivity. A standardized MID and a standardized TCID₅₀ have not been reported previously for any microsporidian species. Both types of doses are reported in this paper, and the values were used to evaluate the effects of chlorine disinfection on the in vitro growth of microsporidia. Spores were treated with chlorine at concentrations of 0, 1, 2, 5, and 10 mg/liter. The exposure times ranged from 0 to 80 min at 25°C and pH 7. MID data for E. intestinalis were compared before and after chlorine disinfection. A 3-log reduction (99.9% inhibition) in the E. intestinalis MID was observed at a chlorine concentration of 2 mg/liter after a minimum exposure time of 16 min. The log₁₀ reduction results based on percent transmittance-derived spore counts were equivalent to the results based on hemacytometer-derived spore counts. Our data suggest that chlorine treatment may be an effective water treatment for E. intestinalis and that spectrophotometric methods may be substituted for labor-intensive hemacytometer methods when spores are counted in laboratory-based chlorine disinfection studies.     

Technological and economic potential of poly(lactic acid) and lactic acid derivatives

Abstract: Lactic acid has been an intermediate-volume specialty chemical (world production ∼ 40,000 tons/yr) used in a wide range of food processing and industrial applications. Lactic acid has the potential of becoming a very large volume, commodity-chemical intermediate produced from renewable carbohydrates for use as feedstocks for biodegradable polymers, oxygenated chemicals, plant growth regulators, environmentally friendly 'green' solvents, and specialty chemical intermediates. The recent announcements of new development-scale plants for producing lactic acid and polymer intermediates by major U.S. companies, such as Cargill, Ecochem (DuPont/ConAgra), and Archer Daniels Midland, attest to this potential.
In the past, efficient and economical technologies for the recovery and purification of lactic acid from crude fermentation broths and the conversion of lactic acid to the chemical or polymer intermediates had been the key technology impediments and main process cost centers. The development and deployment of novel separations technologies, such as electrodialysis (ED) with bipolar membranes, extractive distillations integrated with fermentation, and chemical conversion, can enable low-cost production with continuous processes in large-scale operations. The use of bipolar ED can virtually eliminate the salt or gypsum waste produced in the current lactic acid processes. Thus, the emerging technologies can use environmentally sound processes to produce environmentally useful products from lactic acid. The process economics of some of these processes and products can also be quite attractive. In this paper, the recent technical advances in lactic and polyactic acid processes are discussed. The economic potential and manufacturing cost estimates of several products and process options are presented. The technical accomplishments at Argonne National Laboratory (ANL) and the future directions of this program at ANL are discussed.     

Chlorine inactivation of spores of Encephalitozoon spp

This report is an extension of a preliminary investigation on the use of chlorine to inactivate spores of Encephalitozoon intestinalis and to investigate the effect of chlorine on two other species, E cuniculi and E. hellem, associated with human infection. The 50% tissue culture infective doses of these three species were also determined. On the basis of the results obtained, it appears that chlorination of water is an effective means of controlling spores of these organisms in the aquatic environment.     

Chlorine disinfection of atypical mycobacteria isolated from a water distribution system

We studied the resistance of various mycobacteria isolated from a water distribution system to chlorine. Chlorine disinfection efficiency is expressed as the coefficient of lethality (liters per minute per milligram) as follows: Mycobacterium fortuitum (0.02) > M. chelonae (0.03) > M. gordonae (0.09) > M. aurum (0.19). For a C.t value (product of the disinfectant concentration and contact time) of 60 mg.min.liter(-1), frequently used in water treatment lines, chlorine disinfection inactivates over 4 log units of M. gordonae and 1.5 log units of M. fortuitum or M. chelonae. C.t values determined under similar conditions show that even the most susceptible species, M. aurum and M. gordonae, are 100 and 330 times more resistant to chlorine than Escherichia coli. We also investigated the effects of different parameters (medium, pH, and temperature) on chlorine disinfection in a chlorine-resistant M. gordonae model. Our experimental results follow the Arrhenius equation, allowing the inactivation rate to be predicted at different temperatures. Our results show that M. gordonae is more resistant to chlorine in low-nutrient media, such as those encountered in water, and that an increase in temperature (from 4 degrees C to 25 degrees C) and a decrease in pH result in better inactivation.     

Trade-off Modeling for Product and Manufacturing Process Design for the Environment

This article presents a method for integrating pollution prevention and concurrent engineering (simultaneous design of products and the manufacturing processes used to produce them). The central issue is unavoidable trade-offs, such as those among pollution, manufacturing cost, and quality. The probabilistic nature of the manufacturing process is exploited as an opportunity for pollution preventi0n.A decision tool in the form of a mathematical model is presented, which can be used by engineers and others with whom these trade-offs must be negotiated, Specifically, the method integrates statistical manufacturing process control into a mubobjective design optimization formulation. First, the framework of a multiattribute utilty function is developed to determine which objectives are both relevant and negotiable. Then, a statistical manufacturing process control experiment is conducted to formulate some of the constraints that prevent all objectives from being maximized. Simultaneously, information obtained from the experiment is also used to fine-tune the upper and lower bounds in the utility functions. The results of an industrial case study of a floor tile manufacturer are presented, from the manufacturer's viewpoint. The material choice and manufacturing process settings that result in the best combination of the conflicting objectives of product quality (measured in terms of scrap rate), air pollution, and manufacturing cost are determined. The analysis also reveals the irony that for this manufacturer; efforts to reduce solid waste through greater use of scrap materials increase air pollution levels