30. Solving a chemistry problem

To extract noble metals from aqueous solutions of their salts, it is promising to use extraction with toluene solutions of phosphine oxides. What amount of gold can be extracted from 10 m3 of wastewater containing 1000 mg/l of gold by extraction of 5 m3 of a solution of trioctylphosphine oxide (TOPO) in toluene, if the distribution coefficient of gold in the system water - TOPO solution is 0.0639.