Sorption of cadmium and zinc from aqueous solutions by zeolite 4A, zeolite 13X and bentonite

Iron supported on bioinspired green silica for water remediation

“…V is the volume of the solution (cm 3 ) and W is the mass of sorbent (g) used. 49 where q e (mg g –1 ) and C e (mg dm –3 ) are the equilibrium concentrations of As( v ) in the adsorbed and liquid phases, and q m (mg g –1 ) and b (L mg –1 ) are the Langmuir constants and q m is the maximum monolayer capacity. q e = K f C e 1/ n where K f (mg g –1 ) and n (L mg –1 ) are the Freundlich constants, which are related to the sorption capacity and intensity of adsorption, respectively. The sorption equilibrium data of As( v ) onto Fe-GN were analysed by fitting the data to Langmuir and Freundlich isotherm models using Origin Pro 8.6.…”

Influence of Physical and Chemical Parameters on the Treatment of Heavy Metals in Polluted Stormwater Using Zeolite—A Review

“…Temperature, pH, zeolite concentration and initial metal concentration are the major parameters that are considered to have an effect on the removal of heavy metals. Several studies report the superior heavy metal sorption capacities for zeolites with low Si:Al ratios [38,[41][42][43]. The prominent role played by Si:Al ratio on the sorption of heavy metals has been demonstrated in the study of Leinonen and Lehto [42].…”

“…Strong bases can lead to desilication, whereas strong acids can break Al atoms. Zeolite structure can be destroyed at extreme pH values, which in turn can reduce sorption [40,43]. Since zeolite is capable of changing the pH of the solution, there is a possibility for these processes to occur during the treatment of polluted water.…”

Ag+- and Zn2+-exchange kinetics and antimicrobial properties of 11Å tobermorites

“…Typical equilibrium times for Zn 2+ -uptake by clays (stevensite 44 and bentonite 45 ) and zeolites (A, 46 4A, 45 13X 45 ) are within 2 h of contact and maximum sorption capacities are generally found to be between 0.3 mmol g −1 and 2.5 mmol g −1 . A number of studies has shown that the pseudosecond-order model is representative of these processes and k 2 values in the range 8.3 × 10 −3 to 15.43 g mmol −1 min −1 are reported.…”

“…A number of studies has shown that the pseudosecond-order model is representative of these processes and k 2 values in the range 8.3 × 10 −3 to 15.43 g mmol −1 min −1 are reported. [44][45][46] In comparison, the Zn 2+ -exchange rates for Tob-Na1 (k 2 = 8.50 × 10 −4 g mmol −1 min −1 ) and Tob-Na4 (k 2 = 9.87 × 10 −4 g mmol −1 min −1 ) are considerably slower than those documented in the literature; however, the extents of Zn 2+ -uptake by the tobermorite specimens were found to be towards the top end of the reported range for clays and zeolites. [44][45][46] …”