Reducing phosphine after the smoking process using an oxidative treatment

This article gives a description of the setup in a laboratory of a pilot sy stem to reduce phosphine following the smoking process of foodstuffs. At pr esent, this fumigant is released into the atmosphere and causes serious dam age to the environment due to its transformation into aggressive compounds. However, phosphine may prove a good alternative to methyl bromide, which w ill legally be used as a fumigant until the year 2002, provided it is made inert after the smoking process and transformed into nontoxic and easily di sposable substances. Oxidant solutions containing potassium permanganate or potassium bichromate in suitable concentrations proved moderately effectiv e in reducing phosphine. The addition of traces of silver nitrate as a cata lyst to the oxidant solutions increased the efficiency in reducing the fumi gant, although not completely. Thus it was necessary to use a recycling sys tem to decontaminate air from phosphine, as such an apparatus ensures the c omplete reduction of phosphine. The mathematical function describing how th e concentration of phosphine varies in the smoking chamber also makes it po ssible to estimate the time necessary to reduce a phosphine concentration f rom any initial value to a fixed final value.