Waste solvent disposal

The extract is vacuum-distilled ia the solvent recovery column, which is operated at low bottom temperatures to minimise the formation of polymer and dimer and is designed to provide acryUc acid-free overheads for recycle as the extraction solvent. A small aqueous phase in the overheads is mixed with the raffinate from the extraction step. This aqueous material is stripped before disposal both to recover extraction solvent values and minimise waste organic disposal loads. 

The mobile phase is interesting in that the water is buffered appropriately to complement the dissociation constants of the solutes. A mixture of methanol and acetonitrile is employed, the acetonitrile being used to increase the dispersive interactions in the mobile phase. The reason for the particular solvent mixture is not clear and it would appear that the separation might be achieved equally well by using a stronger solution of methanol alone or a more dilute solution acetonitrile alone. There is no particular advantage to one solvent mixture over another except for the fact that waste acetonitrile produces greater solvent disposal problems than methanol. 

Every laboratory should be equipped with a waste solvent container in which all waste organic solvents and solutions are collected. The contents of these containers should be periodically transferred to properly labeled waste solvent drums and arrangements made for contracted disposal in a regulated and licensed incineration facility. ... 

If arrangements for incineration of waste solvent and disposal of solid chemical waste by licensed contract disposal services are nol in place, a list of providers of such services should be available from a state or local office of environmental protection. 

In addition to being harmful to the individual, many chemicals are hazardous to the environment, so waste chemicals must not be put down the sink or into the rubbish bins unless this is stated to be safe. Waste solvent and reagents must be put into appropriate waste bottles. Chlorinated and nonchlorinated solvents are usually kept separately and then sent for disposal by external contractors. Broken glass or needles and scalpels are to be disposed of in sharps containers. 

The soil in the funnel is washed free of excess reagent by five successive additions of 95% ethanol, allowing to drain between washings. A wash bottle containing ethanol enables the interior surface of the funnel, the outside of the stem, the exposed surface of the paper and the soil to be thoroughly washed. Any remaining ammonium ethanoate will elevate the final CEC value. The washings, which are flammable, should be collected in a waste solvents bottle for safe disposal. 

With aerosol cleaning products, a quick spray and a blow-dry with compressed air, or a wipe with a dry rag or towel is all that is required to remove the unwanted soil. Another benefit of spraying is the motive force of the spray, which assists in soil removal. Because of the tendency for aerosol products to finely atomize the cleaning solvent and increase air emissions, some air-quahty agencies are mandating the use of low-vapor-pressure solvents in hand-pump dispensers. This action reduces solvent loss to the atmosphere and increases the amount of waste solvent, which must be collected and stored for subsequent recycling or disposal. 

CAUTION Chloroform/acetone is explosive if it comes in contact with strong alkali. Waste solvent should be stored in a labeled container strictly used for disposal of these solvents, and not mixed with other materials. Disposal is conducted according to implemented safety guidelines of the institution. If there is a possibility of the waste turning alkaline, some hydrochloric acid should be added to ensure it remains acidic. 

SFC provides complementary quantitative data to the structural information afforded by mass spectrometry. Thermally label materials such as isocyanates can be easily analyzed with minimal sample preparation. Supercritical carbon dioxide is nontoxic and can be obtained in high purity as measured by FID. The easy coupling of SFE with SFC makes the selective isolation and quantification of targeted analytes possible. Furthermore, we are in an age of increased environmental awareness. Solvent disposal is discouraged and has become very expensive. The waste disposal costs associated with supercritical carbon dioxide are negligible when compared to the solvent disposal costs generated by traditional Soxhlet methods. 

Wear PVA or Viton gloves,18 laboratory coat, and eye protection. Avoid breathing vapor. Recycle by distillation (in a fume hood) or place waste in halogenated solvent-disposal container for disposal by burning. Dissolve the compound in a nonchlorinated flammable solvent and spray into a furnace with afterburner and scrubber.20,21... 

Waste quantities can be recovered for reuse by distillation. Otherwise, place in a solvent disposal container for disposal by burning in a chemical incinerator equipped with afterburner and scrubber.6,8... 

Place waste methanol in nonhalogenated waste solvent container labeled for disposal by burning.15... 

Place waste in nonhalogenated solvent disposal container for disposal by burning.8... 

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