Slow-release of methanogenic inhibitors derived from encapsulated calcium carbide using paraffin wax and/or rosin: matrix optimization and diffusion characteristics

Abstract

Acetylene has been found to significantly inhibit biological activity of methanogens and thus might be applicable for reducing the generation and emission of methane from municipal solid waste landfills. However, acetylene is gaseous and so it is considered physically infeasible to directly apply this gas to waste in landfill conditions. In the present study, a novel acetylene release mechanism was tested, using a matrix of acetylene entrapped in high hydrophobic paraffin wax and/or rosin and calcium carbide capsules with a ratio of 1.0 g g−1 matrix and a diameter of 10 mm to facilitate the gradual release of acetylene. A diffusion mechanism model ( Q = ɣ × t0.5) for the matrix was derived based on the T. Higuchi equation, and the effective diffusion coefficients ( De) were acquired by linear fitting. Additionally, it was found that De remained constant when the rosin content was up to more than 20% g g−1 matrix.