Abstract: A process for removal and recovery of arsenic from a gas comprising contacting a supported sorbent with an arsenic-containing gas, adsorbing the arsenic with the supported sorbent, desorbing the arsenic from the supported sorbent, and collecting the desorbed arsenic.

Abstract: A process for pretreating oil shale prior to retorting by contacting with an organic acid, such as formic and acetic acids, at temperatures below about 100.degree. C. for a period of time sufficient to react at least a portion of the oil shale carbonates and separating the shale from the organic acid solution containing at least a major portion of the reaction products of the carbonates and organic acid. The process is preferably carried out in an aqueous solution of organic acid having a pH of 3 and less for a time of about 1/2 to about 4 hours and at ambient temperatures about 20.degree. to about 30.degree. C. Pretreatment of oil shale by this process prior to retorting results in higher liquid and aromatic product fractions being produced by conventional retorting.