. "Nonlimiting separation techniques or methods include filtration, gravity settling, centrifugation, flocculation, cake filtration, membrane filtration, and floatation (liquid/air filtration). [0015] One group of thiurams can be characterized by the general chemical formula (I), as illustrated below. [0016] wherein, m is an integer of 1 or 2; and R1, R2, R3, and R4 are individually selected from the" . . .