Abstract: The simultaneous abatement of NO and SO.sub.2 in flue gas is provided by an absorption process and apparatus utilizing an absorbent composition comprising an aqueous solution of chelates and sulfite salts. Metal chelates oxidized to an inactive state are electrochemically reduced. In the electrochemical cell, nickel or stainless steel anode materials are stable and may be used in the place of platinum coated anode materials when the anolyte pH is maintained greater than 12. At these conditions, the anode is corrosion resistant with a long operating time between replacement. Ultrafiltration or Donnan dialysis may be used to separate the chelate sorbents from the waste salts to reduce the loss of expensive chelate sorbents. Alternatively, an anionic exchange membrane can be used to electrodialytically separate waste sulfur/nitrogen salts from the absorbent solution.

Abstract: An aqueous formulation for cleaning grease and oil from metal, plastic, glass or other surfaces includes water, a surfactant, and a corrosion-inhibiting amount of a 2-piperazinone. The surfactant is chosen from the class of materials possessing at least some ability in aqueous solution to disperse the grease and oil in an aqueous suspension. The formulation preferably includes both an anionic and a nonionic surfactant. The 2-piperazinone inhibits corrosion of the metal or other surface without unduly reducing the dispersive ability of the surfactant(s). The preferred 2-piperazinones for use in the disclosed invention are 4-(2-hydroxyethyl)-2-piperazinone (4-HEP) and N,N-dimethyl-2-piperazinone (NNDP). The formulation is used by agitation in contact with the surface to be cleaned, for example, by mechanical agitation of the surface, by spraying the formulation against the surface, or by the application of ultrasound waves.