Abstract: Hydroxy and alkyloxy benzophenones, also known as arylphenones, are efficiently and economically purified by contacting them with inorganic phosphorous compounds in the presence of a non-polar solvent. Best results are obtained when the arylphenone is then treated with an activated carbon and/or activated clay.

Abstract: A composition for plugging wells that is biodegradable and environmentally safe comprising bentonite particles coated with a water soluble coating of biodegradable natural resin, such as certified three pound Confectioners White Lac Glaze in Specially Denatured Ethyl Alcohol (SDA) Formula 35A, 190 proof. The bentonite may be in the form of chips or compressed pellets. When exposed to water, the soluble coating dissolves at a uniform rate, exposing the bentonite to water whereupon it expands to form a tough but flexible water impermeable seal of a semi-solid, gel-like mass.

Abstract: An improved rotary filter is cylindrical in shape, and operates by vacuum suction or otherwise to withdraw fluids from a substance exposed to the outer area of the device, drawing said fluids into the filter to be pumped out to a suitable reservoir. It includes an inner cylindrical surface having attached thereon a plurality of selectively spaced support structures which extend longitudinally along the inner cylinder. Said support structures are covered with a plastic covering adapted to receive a filtering medium which forms the outer circumference of the rotary filter. In one embodiment the plastic covers are grooved to receive a spirally wound wire to further support said filtering medium.