Macroporous Weak-Acid Cation Exchange Resin with
Chelating Isothiouronium Group
for Mercury Removal and Precious Metal Recovery


D740 is a macroporous styrene-based ion exchange resin containing isothiouronium as chelating functional groups. Attributed to its peculiar chelating groups, large porosity and firm structure, D740 performs excellent chemical stability in larger capacity in selective removal of mercury(Hg) and exclusive separation of precious metals as gold(Au), Platinum(Pt) or Palladium(Pd), regardless of being surrounded by heavy metals as sodium(Na), alkaline-earth metals(ie.Ca, Mg), or ferrous(Fe) & copper(Cu).

Due to its strong affinity to free mercury, the chelating groups tightly bind to divalent Hg ions to form highly stable complexes, D740 is specialized in removing dissolved mercury salts in wastewater. Besides, it is also widely being used for precious metals recovery from rinse water in electroplating and electronics industries as well as in hydrometallurgy such as gold separation from acid solutions. 

Please note that D740 is designed as a hard-to-regenerate model for its rather strong adsorption chelating groups and least elutable features, which is suggested being operated under systems in acid solutions.

Matrix: Styrene-divinylbenzene copolymer
Physical form: Milk white opaque spherical beads
Functional groups: -CH2-S-C=NH-NH2
Moisture holding capacity(%): 48 to 58%
Ionic form as shipped: H+ form
Specific gravity: 1.11
Adsorption capcity of Hg2+: ≥150g/L
Total bulk exchange capacity: ≥1.2mmol/mL
Moisture true density: 1.10~1.16g/mL
Moisture bulk density: 0.70~0.76g/mL
Particle size: 0.45~1.25mm ≥95℅
Uniformity coefficient: ≤1.6
Integrated beads ratio after grinding test: ≥95℅
Temperature limit: 60 °C (140.0 °F)

Maximum operating temperature: 80°C
Minimum bed depth: 1000mm
PH range: 0-7
Service flow rate: 5~30 BV*/h
Backwash linear velocity: 4~10 m/h
Backwash duration: 30min
Slow rinse: 2 BV at regeneration flow rate
Fast rinse:4~8 BV at service flow rate
*1 BV(Bed Volume)= 1m3 solution per m3 resin