One of the priority issues in green chemistry is to devise of greener and sustainable chemical strategies and processes to reduce or eliminated the use of hazardous substances. The development of bio-based materials has been constantly increasing, and there is a global effort in agreement with the demands of sustainable management for reducing reliance of fossil resources. In this sense there are green polymerization systems improved to reach increased yields and produce polymers with high molar mass and with specific microstructure characteristics. In the same way, biocatalysis in green chemistry reactions are performer under mild conditions of temperature, pressure and pH. However, along with new materials, chemical processes and reactors must be redesign and developed to guarantee the requirements and meet the demand for green chemical products. Substantial differences with traditional chemical process are based on the synthesis of materials changing the solvents selections and the implementation of continuous reactors, as well as in evaluating the effectiveness of the process through factors such as atom economy, environmental factor, and process mass intensity to implement an industrial green process. This chapter is a review of the processes that have been design and developed to achieve to maximize efficiency and reduce waste.
To prepare for spills, you should: (1) learn about the hazards of the chemicals in your laboratory, (2) write response procedures to address those hazards, and (3) make sure that you have the equipment and training necessary to follow those procedures.
As an integral part of any laboratory work, you must identify the hazardous or potentially hazardous properties of all chemicals used or produced in your laboratory. Before using any chemicals, you should evaluate the consequences of potential spills and develop appropriate response procedures. If necessary, consult published data (such as material safety data sheets and chemical dictionaries) for response planning. Additionally, communicate potential hazards to other workers in your area.
When planning laboratory work and preparing for potential problems, determine the hazard class of all the chemicals to be used. The following chemical properties are of most concern when preparing for possible chemical spills:
Every laboratory should develop written spill response procedures. Such procedures should detail the initial steps to take when a spill occurs and include such elements as staff responsibilities, communication methods, instructions on using spill response equipment, and spill cleanup and residue disposal. Communicate these procedures to all individuals who use chemicals or who might assist during spill cleanup. Periodically review and update these procedures to ensure that all laboratory workers are familiar with the current information. Each procedure should indicate the date it was last reviewed. The laboratory's Chemical Hygiene Plan is a good place to include these procedures.
Before starting any work with chemicals, verify that all necessary safety equipment and spill cleanup materials are available and in good working order. Additionally, ensure that the individuals who may be involved in spill response are properly trained in equipment use and spill cleanup procedures. Finally, regularly inspect all materials and equipment to ensure that they will function properly when needed.
If the potential for fire or explosion exists, seek outside assistance from trained emergency responders. Releases of flammable chemicals (liquid or solid) can present significant fire and explosion risks when one or more of the following is present:
Though small amounts of some chemicals pose environmental problems, most environmental risks are presented by large-quantity releases of materials. A large-quantity release that threatens the environment is not a simple spill, but requires the attention of trained responders.
The more toxic, corrosive, or flammable a material is, the less likely that the spill can be defined as "simple". Thresholds for flammable liquids and solids, as well as volatile toxics, should be relatively low. Spills of reactive chemicals should only be managed by trained responders (who may be in-house). In general, simple spill thresholds for liquids will be lower than the thresholds for solids. Additionally, simple spill thresholds for volatiles will be lower than the thresholds for non-volatiles.
The third step to take when deciding whether a spill can be managed as a simple spill is to evaluate the potential broader impacts of the spill. A chemical spill in an area where its potential risks are magnified by specific situations (such as physical situations or the presence of a large number of people) should not be managed as a simple spill. For instance, the presence of boxes, chemicals, and other ignition sources would magnify the impact of a one-gallon release of acetone. Since acetone is highly flammable and volatile, this situation would be immediately dangerous to both human health and property, and cleanup should be handled by an emergency responder. Other factors that may magnify a spill's impact and require emergency response are
Add absorbents to the spill, working from the spill's outer edges toward the center. Absorbent materials, such as cat litter or vermiculite, are relatively inexpensive and work well, although they are messy. Spill pillows are not as messy as other absorbents, but they are more expensive. Note that special absorbents are required for chemicals such as hydrofluoric and concentrated sulfuric acids.
Laboratories seeking to minimize and prevent spills should consider the possible results of their choices and procedures. Such consideration should focus on reducing the likelihood of spills, as well as minimizing spill damage. Experimental plans should only involve chemicals that are actually needed for the desired results. Ideally, laboratories should only store chemicals that will be used within a reasonable period of time. Additionally, correct chemical and experimental equipment choices must be made. Finally, the laboratory worker must not settle for inappropriate laboratory arrangements.
Any chemical that presents a threat to the environment is defined by the Environmental Protection Agency (EPA) as a hazardous substance. The Agency assigns each hazardous substance a reportable quantity (RQ), which is based on a chemical's inherent risk properties. Virtually all common laboratory chemicals are on this hazardous substance list. While some hazardous substances have RQs as low as one pound, typical RQs are larger than the amounts found in laboratories. All chemical hazardous wastes have an RQ of one pound. A list of reportable quantities can be found in 40 CFR 302.4 (Code of Federal Regulations, Protection of Environment, Designation of Hazardous Substances).
Preplanning with local emergency responders is required if a laboratory has "environmentally hazardous substances" exceeding threshold planning quantities. As with reportable quantities, threshold planning quantities vary according to each chemical's inherent hazards. Although few laboratories have sufficient quantities of hazardous chemicals to be subjected to these requirements, preplanning can help avoid miscommunication with local emergency responders. A list of threshold planning quantities is found in 40 CFR 355 (Emergency Planning and Notification) Appendices A and B.
In addition to chemical spills, water spills can be caused by loose connections or breaks in lines to water condensers or cooling systems. Such spills can cause damage and inconvenience, even if they do not present environmental or health risks. Appropriate planning, including use of security clamps or other devices to prevent loosening of connections or automatic shut-off devices, can reduce the likelihood of flood damage. Occasionally, a laboratory may be affected by a leaking roof or a flood elsewhere in a building. Planning to prevent damage from incidents should include the protection of instruments that might be harmed by water. Similarly, storing chemicals and supplies so that they will not be touched by leaking water will minimize damage and inconvenience.
Edited by the inventor of the 12 principles of Green Chemistry, Paul Anastas, the complete 12-volumes of "Handbook of Green Chemistry" will provide a one-stop resource covering green catalysis, green solvents, green products and green processes."Handbook of Green Chemistry" covers highly topical areas in green chemistry such as feedstocks, green chemical engineering, green catalysis (homogeneous, heterogeneous and biocatalysis), separation techniques and solvents like supercritical fluids, ionic liquids and reactions in water. It covers the big environmental and product design issues faced by chemists such as how to make nanoscience greener, design safer, sustainable and less toxic chemicals and make chemical synthesis a greener and more sustainable process. In the final 3 volumes, "Handbook of Green Chemistry" will cover green products, the chemical engineering behind their processing and what makes a green product, vital in now this is key selling point for industry.
Set one of this essential collection of essays summarizes breakthroughs and highlights of the significant body of innovative, creative research in green chemistry and engineering that has been carried out during the past decade. It augurs well for the forthcoming sets of the series, and I am pleased to recommend it to chemists, chemical engineers, and anyone who wishes to understand the burgeoning world of green chemistry.- Chemical & Engineering News, May 2010
If a chemist specializes in green chemistry, he or she will design chemical processes and products that are environmentally sustainable. Green chemistry processes minimize the creation of toxins and waste.
Chemists and materials scientists may be exposed to health or safety hazards when handling certain chemicals, but there is little risk if they follow proper procedures, such as wearing protective clothing when handling hazardous chemicals. 2b1af7f3a8