Spill mix

Wear nitrile rubber gloves, laboratory coat, and self-contained breathing apparatus. Cover the spill with a 1 1 1 mixture by weight of sodium carbonate, clay cat litter (calcium bentonite), and sand. When all of the liquid has been absorbed, scoop the mixture into a plastic pail or other wide-mouth container and place in the fume hood. If local regulations permit, allow the acetone vapor to evaporate for several days until no odor remains. The spill mix can then be discarded with normal refuse.14,15 Otherwise, package and label for disposal by burning.15,16... 

Wear breathing apparatus, eye protection, laboratory coat, and butyl rubber gloves. Cover spill with 1 1 1 mixture by weight of sodium carbonate or calcium carbonate, clay cat litter (bentonite), and sand.8 For each 1 mL of iron pentacarbonyl, place 45-50 mL of household bleach (about 5% sodium hypochlorite solution) in a plastic bucket equipped with a stirrer and located in a fume hood. Dilute the bleach with three times its volume of water and, to this solution, slowly add the contaminated spill mix while stirring. Continue the stirring for a period of 48 hours, and then filter the slurry using vacuum filtration. The... 

In the event of a spill, mix the spilled material with water-wetted vermiculite or sand or any other inert moist diluent and place it in a plastic container for immediate disposal. Do not nse paper, wood, or cellulose material or spark-generating tools. 

In the event of a spill, mix acrylamide with an absorbent material (avoid raising dust), place in an appropriate container, and dispose of properly. Evacuation and cleanup using respiratory protection may be necessary in the event of a large spill or release in a confined area. 

We have tested the spill mix in the laboratory on simulated spills of over 250 hazardous chemicals and their solutions. Three characteristics were measured. First, we looked at the ability of the spill mix to absorb liquids and eliminate toxic and/or flammable fumes. Secondly, we assessed its effectiveness in reducing the danger of highly reactive solids catching fire. Thirdly, we determined methods by which the spill mix containing the absorbed spill could be converted to environmentally safe products for disposal. 

The general procedure for using spill mix is to pour the spill mix onto the spill of liquid or reactive solid so that all of the liquid is absorbed or all of the reactive solid is completely covered. The residue is scooped up using a plastic scoop and placed in a plastic pail. For off-site disposal, the residue is packaged, labeled appropriately, and sent for disposal. In many cases the residue can be converted at the laboratory bench to nontoxic and nonhazard-ous residues for easier disposal. Some of the methods developed and tested in the laboratory to facilitate on-site disposal are described in Section 29.3. To ensure a fast cleanup, spill kits including gloves, goggles, plastic pail, plastic scoop, and step-by-step cleanup procedures should be readily available. 

To treat a spill of a mineral acid, such as concentrated hydrochloric, sulfuric, or nitric acids, breathing apparatus must be worn in addition to appropriate protective equipment. If the spill is of a dilute aqueous solution of a mineral acid, breathing apparatus may not be necessary. The spill is covered with spill mix until all of the liquid is absorbed. A plastic pail is three-quarters filled with water and the residue is transferred into the pail of water using a plastic scoop. The pail is transported to a fume hood. The pH of the solution is measured and, if necessary, the solution is neutralized by the addition of sodium carbonate or dilute (5%) aqueous sodium hydroxide solution. 

Table 29.1 lists the approximate quantities of spill mix required for spills of 100 mL of the given liquids and the approximate volumes of 5% aqueous sodium hydroxide needed to neutralize the resultant solution when the spill mix is added to 5 L of water. After standing in the fume hood until the solids have settled, the liquid containing sodium chloride, sodium sulfate or sodium nitrate in aqueous solution is poured into the drain. The solids, bentonite and sand, are treated as non garbage. When the aqueous acidic solution is neutralized with sodium carbonate or aqueous 5% sodium hydroxide solution, the acids are converted to their sodium salts as shown in Eqs. (29.1) and (29.2) respectively... 

TABLE 29.1 Quantities of Spill Mix Required to Absorb Some Acids and Bases and Volumes... 

Liquid spilled (100 mL) Weight of spill mix used Volume of 5% aqueous NaOH to give pH 7 Volume of 5% aqueous HCl to give pH 7... 

Table 29.1 lists the approximate quantity of spill mix required for a spill of 100 mL of 20% sodium hydroxide solution and the volume of 5% aqueous hydrochloric acid required to bring the solution formed by the addition of the absorbent to 5 L of water to pH 7. After the solids have settled, the neutral aqueous liquid is decanted to the drain and the solid residue, consisting of sand and bentonite, can be discarded as normal garbage or washed with water, dried, and reused in spill mix. Neutralization of the spilled base with sodium bisulfate or 5% aqueous hydrochloric acid solution occurs according to Eqs. (29.3) and (29.4) respectively. 

Spills of ammonia present two hazards. Laboratory workers may slip in the spill or be overcome by the vapors, especially if the ammonia is a concentrated solution. Thus, the worker handling the spill should wear breathing apparatus and other people should remain a safe distance away. The spill is covered with sufficient spill mix to absorb all of the liquid and maintain a dry layer of spill mix on top. The mixture is scooped into a container and transported to the fume hood. In the fume hood it is slowly added to a plastic pail of cold water. The liquid is neutralized by the addition, with stirring, of either solid sodium bisulfate or 5% aqueous hydrochloric acid. The aqueous solution is decanted into the drain and the solid, sand/bentonite, disposed as normal garbage or washed with water, dried, and reused... 

Examples of fiammable solvents are methanol, ethanol, acetone, diethyl ether, and hexane. Several of these liquids have toxic fumes but the greatest hazard of spills of these highly fiammable liquids is the risk of fire. When a spill occurs, all ignition sources should be immediately shut off. Covering the spilled liquid with spill mix rapidly eliminates further... 

Spills of aqueous solutions containing heavy metal salts present a disposal problem since many of these salts are highly toxic and should not be disposed in such a way that they will contaminate groundwater. The spill is covered with sufficient spill mix to absorb all of the liquid. The mixture is scooped into a container and transported to the fume hood. Sufficient water is added to dissolve the sodium carbonate in the spill mix. The solids are allowed to settle and the supernatant liquid decanted into another container. The solids are washed with water, allowed to settle, and the washings are added to the decanted liquid. An aqueous solution of sodium metasilicate (Na2Si03 5H2O, 12.5 g per 100 mL of water) is added, with stirring, until there is no further precipitation of solid. 

When a chemical is especially hazardous to the worker handling the spill, it is advisable to try to neutralize the spill before absorption onto spill mix. Such treatment is especially recommended when the spilled material is a known human carcinogen. Many of the chemicals used in chemotherapy are known to be mutagenic and therefore have the potential to be carcinogens. For example, daunorubicin is deactivated with acidic potassium permanga-... 

For spills of solid unknown substances, a judgment has to be made about the probable hazard of the spill. It is always wise to assume the worst-case scenario and wear complete personal protective equipment with breathing apparatus. If it is known that the solid is not dangerously reactive, then it can be scooped into a container, packaged, and labeled as accurately as possible for disposal. If there is a possibility that the spill is of a metal hydride or other solid that may spontaneously catch fire, it should be covered with spill mix, scooped into a plastic pail using a plastic scoop, and transported to the fume hood. Slowly and cautiously, butanol is added with stirring to the mixture. The weight of hydride spilled is estimated and about 40 mL of butanol is allowed for each 1 g of mixture... 

If the spill is of a liquid, it should be covered with spill mix as quickly as possible until all the liquid is absorbed and there is a dry layer of spill mix on top. If the spill is known to be of a flammable organic solvent, although the exact identity of the liquid is unknown, the adsorbed residue can be treated as described under Section 29.3.5. Similarly, if the spill is known to be of an aqueous solution containing heavy metal ions, the procedure described in Section 29.3.7 can be followed. If the nature of the liquid is completely unknown, either it can be analyzed to discover its identity and the residue can then be treated appropriately, or the residue from absorption on spill mix can be packaged, labeled as accurately as possible, and sent off-site for disposal. 

For the over 250 hazardous chemicals that we have spilled and tested with spill mix, it has been found that liquids are rapidly absorbed and fuming is quickly eliminated. Because the spill mix is relatively inexpensive, containers of it can be kept in laboratories or other areas where hazardous chemicals may be spilled. This allows for very rapid covering of the spill with spill mix and the control of many of the risks associated with the spill. The spill mix we have developed is versatile and provides a practical way of reducing the danger of spills of hazardous chemicals. When the identity of the spilled chemical is known, it is often possible to convert the absorbed mixture to environmentally acceptable products using reactions that have been tested in the laboratory. 

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