® M e r c a p t a n O d o r C o n t r o l CAIROX POTASSIUM PERMANGANATE TECHNICAL BRIEF BACKGROUND In municipal and industrial waste treatment, hydrogen sulfide is not the only offensive gas generated from anaerobic decomposition. Mercaptans (RSH) are the organic equivalent to hydrogen sulfide and more odorous at 1/1000th the concentration. Mercaptans are naturally occurring from the degradation of sulfur containing organics (proteins, etc.). A table of commonly found mercaptans is presented on the reverse side. Oxidation is the only method that completely eliminates mercaptan odors. Precipitation technology may adsorb some mercaptans, but may readily release the adsorbed molecules. Removal of sulfide by precipitation often allows the odor from mercaptans to be more apparent and equally offensive. A comparison of mercaptan removal technologies is given below. The first step in oxidation is the formation of disulfide (RSSR) and this is ultimately oxidized to the non-odorous Sulfonic Acid (RSO3H). Chemical Dosage (mg/L) 40 Iron Salts 1456 Peroxide 420 L 35 ® / CAIROX 177 g m , 30 n o i t a r 25 t n e c 20 n o C n 15 a t p a c 10 r e M 5 0 None Iron Salts(1) Peroxide(2) CAIROX®(3) Chemical Treatment (1) Iron Salts react by adsorbing on a precipitate, (reversible release). (2) Peroxide reacts by oxidizing to disulfide, (incomplete removal). (3) CAIROX® reacts by oxidizing to disulfide and by further oxidation to sulfonic acid, (complete removal). Copyright 2000 rev. 03/14 Form # CX 4901 The information contained herein is accurate to the best of our knowledge. However, data, safety standards and government regulations are subject to change; and the conditions of handling, use or misuse of the product are beyond our control. Carus Corporation makes no warranty, either expressed or implied, including any warranties of merchantability and fitness for a particular purpose. Carus also disclaims all liability for reliance on the completeness or confirming accuracy of any information included herein. Users should satisfy themselves that they are aware of all current data relevant to their particular use(s). Carus and Design is a registered service mark of Carus Corporation. CAIROX® is a registered trademark of Carus Corporation. Responsible Care® is a registered service mark of the American Chemistry Council. ® M e r c a p t a n O d o r C o n t r o l CAIROX POTASSIUM PERMANGANATE TECHNICAL BRIEF Oxidation of mercaptans proceeds in a stepwise fashion. Disulfide first is formed before leading to sulfonic acid as the final product. Mercaptan (RSH) Disulfide (RSSR) Sulfonic Acid (RSO3H) 1) Iron Salts Adsorption Incomplete 2) Hydrogen Peroxide Incomplete 3) CAIROX® Complete Removal Efficiency CAIROX® Potassium Permanganate and hydrogen peroxide can both form the disulfide, however, peroxide requires a catalyst and is slow reacting. The disulfide is a water soluble molecule which can readily revert to mercaptan. Disulfides often retain the odor of the mercaptan and are bio-inhibitory. The uniqueness of CAIROX usage is that it will immediately and completely oxidize the mercaptans and disulfide as it is formed. CAIROX provides the most effective and immediate elimination of this serious odor problem. Reactivity ® Substance Characteristic Odor CAIROX Hydrogen Iron Salts Odor Threshold Peroxide ppm KMnO H O Fe +2 and Fe 4 2 2 +3 Allyl Mercaptan Strong garlic - coffee 0.00005 Immediate CAT 1 N/A 2 Amyl Mercaptan Unpleasant - putrid 0.0003 Immediate CAT 1 N /A 2 Benzyl Mercaptan Unpleasant - strong 0.00019 Immediate CAT 1 N/A 2 Crotyl Mercaptan Skunk - like 0.000029 Immediate CAT 1 N/A 2 Diemethyl Sulfide Decayed Vegetables 0.0001 Immediate CAT 1 N/A 2 Ethyl Mercaptan Decayed cabbage 0.00019 Immediate CAT 1 N/A 2 Met hyl Mercaptan Decayed cabbage 0.0011 Immediate CAT 1 N/A 2 Propyl Mercaptan Unpleasant 0.000075 Immediate CAT 1 N/A 2 Sulfur Dioxide Pungent, irritating 0.009 Immediate CAT 1 N/A 2 Tert - butyl Mercaptan Skunk, unpleasant 0.00008 Immediate CAT 1 N/A 2 Thiocresol Skunk, rancid 0.000062 Immediate CAT 1 N/A 2 Thiophenol Putrid, garlic - like 0.000062 Immediate CAT 1 N/A 2 1. Requires catalysis for reaction, slow reaction with catalysis. 2. N/A - No affect (Adsorption is reversible). Adapted from : Odor Control for Wastewater Facilities. Manual of Practice No. 22, Water Pollution Control Federation, Washington, DC, 1979. Copyright 2000 rev. 03/14 Form # CX 4901 The information contained herein is accurate to the best of our knowledge. However, data, safety standards and government regulations are subject to change; and the conditions of handling, use or misuse of the product are beyond our control. Carus Corporation makes no warranty, either expressed or implied, including any warranties of merchantability and fitness for a particular purpose. Carus also disclaims all liability for reliance on the completeness or confirming accuracy of any information included herein. Users should satisfy themselves that they are aware of all current data relevant to their particular use(s). Carus and Design is a registered service mark of Carus Corporation. CAIROX® is a registered trademark of Carus Corporation. Responsible Care® is a registered service mark of the American Chemistry Council. .