Spills solvents

Store flammable solvents safely. Keeping solvent containers in cabinets below bench tops rather than on or above them helps to keep fires small. Large amounts of solvents should be stored in metal containers, since large glass containers are relatively easily broken and the spilled solvent can be the cause of a very serious fire. 

Flammable solvents. Fast action is crucial when a flammable solvent of relatively low toxicity is spilled. This category includes petroleum ether, pentane, diethyl ether, dimethoxyethane, and tetrahydrofuran. Other workers in the laboratory should be alerted, all flames extinguished, and any spark-producing equipment turned off. In some cases the power to the laboratory should be shut off with the circuit breaker, but the ventilation system should be kept running. The spilled solvent should be soaked up with spill absorbent or spill pillows as quickly as possible. These should be sealed in containers and disposed of properly. Nonsparking tools should be used in cleanup. 

Note that Al, varies directly with the surface concentration Q but only with the square root of time. In Practice Problem 4.3, use will be made of Equation 4. lie to estimate the time required for spilled solvent to evaporate into the atmosphere. 

Solubility — the amount of a given substance (the solute) that dissolves in a unit volume of a liquid (the solvent). This property is of importance in the handling and recovery of spilled hazardous materials. Water-insoluble ehemicals are much easier to reeover from water than spills of water-soluble chemicals. Acetone, which is miscible/soluble in water in all proportions, is not readily reeoverable from water. In contrast, benzene, which is lighter than water and insoluble as well, can be readily trapped with a skimmer. For organie eompounds, solubility tends to deerease with inereasing moleeular weight and ehlorine content. 

The materizils in current use have limited resistance to the broad ranges of commonly spilled chemicetl solvents. In fact, no one suit material is known to resist attack by all chemicals. Rubber or polymeric materials eire all permeable to some degree but for some chemicals, there is no acceptable gairment available to provide adequate protection for the wearer. Consequently chemiczil response teams must rely on an inventory of suits constructed of different materials to provide adequate personnel protection. 

Remediation of groundwater impacted by dense phase chlorinated solvents is more difficult than spills of chemicals such as gasoline or diesel fuel. Gasoline and diesel fuel are less dense than water and tend to float near the surface of the watertable. 

Service company wastes such as empty drums, drum rinsate, vacuum truck rinsate, sandblast media, spent solvents, spilled chemicals, and waste acids... 

Basic Explosives Manufacture. The major quantities and the toughest problems are here. They include a) acid waters, treated with lime or soda ash, chemical washes, spills, washdowns b) Red Water from TNT purification. A complex, brick-red soln of Na nitrate, Na sulfate, Na sulfite, Na nitrite, and about 17% organics which include sulfonated nitrotoluene isomers and complex, unidentified dye-bodies c) dissolved expls, eg, Pink Water which is approx lOOppm TNT in w d) suspended expl particles — dust and chips and e) sometimes solvents such as acet, benz, and dimethyl aniline... 

Nonpolarizable interfaces correspond to interfaces on which a reversible reaction takes place. An Ag wire in a solution containing Ag+ions is a classic example of a nonpolarizable interface. As the metal is immersed in solution, the following phenomena occur3 (1) solvent molecules at the metal surface are reoriented and polarized (2) the electron cloud of the metal surface is redistributed (retreats or spills over) (3) Ag+ ions cross the phase boundary (the net direction depends on the solution composition). At equilibrium, an electric potential drop occurs so that the following electrochemical equilibrium is established ... 

An accomplished architect once recommended a certain type of rubber tile for a laboratory floor because his data indicated its superior resistance to acids. He had not bothered to find out whether or not acid spills would be a problem in this case. They would not, in fact. Solvent spills, on the other hand, were quite likely to occur, and the recommended tile had poor solvent resistance. This example illustrates two things the importance of the laboratory operator s involvement with details that are sometimes overlooked even by experts, and the need to study each laboratory s requirements individually. 

Rubber is vulnerable to attack by many organics and should be avoided by laboratories using certain solvents. On the other hand, it has a high resistance to many inorganic chemicals and is often preferred in facilities where such materials are likely to be spilled. Like vinyl, it is available in both sheet and tile form. 

SafeChem, a subsidiary of Dow, has developed a handling system for chlorinated solvents that allows them to be used in closed-loop degreasing systems. The Safe-Tainer system uses two dedicated double wall containers one to hold fresh solvent and the other used solvent. The containers are connected to the cleaning equipment with zero dead volume, leak-free connections that prevent spills, leaks or vapour emissions during use. Used solvent is collected for recycling and professional disposal of any residues. The system minimises solvent use and release to the environment. A study carried out by Dow during a trial in... 

Modem oil spill-dispersant formulations are concentrated blends of surface-active agents (surfactants) in a solvent carrier system. Surfactants are effective for lowering the interfacial tension of the oil slick and promoting and stabilizing oil-in-water dispersions. The solvent system has two key functions (1) to reduce the viscosity of the surfactant blend to allow efficient dispersant application and (2) to promote mixing and diffusion of the surfactant blend into the oil film [601]. 

Dispersant compositions for the treatment of oil spills at the surface of the water consist of a mixture of water, a hydrocarbon solvent, and a mixture of surfactants consisting of 55% to 65% by weight of emulsifiers and 35% to 45% by weight of dioctyl sodium sulfosuccinate. The emulsifying agents consist of a mixture of various sorbitan oleates [351-354]. 

A proteinaceous particulate material has been described that is effective as an oil spill-dispersant composition [1450]. The material is a grain product (such as oats) from which lipids are removed through organic solvent extraction. When such compositions are applied to an oil spill, they will adsorb oil, emulsify it, and finally, disperse it. Moreover, the compositions are substantially nontoxic. 

The picture of the compact double layer is further complicated by the fact that the assumption that the electrons in the metal are present in a constant concentration which discontinuously decreases to zero at the interface in the direction towards the solution is too gross a simplification. Indeed, Kornyshev, Schmickler, and Vorotyntsev have pointed out that it is necessary to assume that the electron distribution in the metal and its surroundings can be represented by what is called a jellium the positive metal ions represent a fixed layer of positive charges, while the electron plasma spills over the interface into the compact layer, giving rise to a surface dipole. This surface dipole, together with the dipoles of the solvent molecules, produces the total capacity value of the compact double layer. 

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