Removal of mercury from its aqueous solution using charcoal-immobilized papain (CIP)

Removal of mercury (II) from aqueous solution using papain immobilized on alginate bead: Optimization of immobilization condition and modeling of removal study

“…Specific Enzymatic Activity (SEA) was determined spectrophotometrically extending the standard assay method for applying it to the solid immobilized sample (Arson, 1970;Dutta et al, 2009). The protocol for estimation of SEA of immobilized papain sample was same as that described by Dutta et al (2009).…”

“…The protocol for estimation of SEA of immobilized papain sample was same as that described by Dutta et al (2009). The only difference lies in the process is that here 0.5 g of AIP was incubated with the freshly prepared casein solution (Hammerstein quality, SRL).…”

“…Determination of temperature optima, pH optima, temperature stability and pH stability Temperature optima and pH optima of AIP were determined by measuring SEA at different temperatures and pH following the protocol as described by Dutta et al (2009). Temperature stability of AIP was assessed by exposing AIP to different temperatures (30-70°C) for 1 h and enzyme assay was performed at 35°C following the same protocol.…”

“…For determination of pH stability, AIP was incubated in different pH (4-9) at room temperature for 1 h. It was then washed thoroughly with distilled water. SEA of washed AIP was determined at 35°C at a constant pH (Dutta et al, 2009). The stability of AIP was determined on the basis of SEA.…”

“…In recent years considerable attention has been given to remove mercury by adsorption process on various adsorbent (Dutta et al, 2009;Ghodbane and Hamdaoui, 2008;Krishnan and Anirudhan, 2002;Lohania et al, 2008;Natale et al, 2006;Rmalli et al, 2008;Velicu et al, 2007). It has been seen that papain, a proteolytic enzyme, has the characteristic of metal binding capability due to presence of sulfhydryl group in its active site and on immobilization over activated charcoal can be used for removal of mercury from its simulated aqueous solution (Dutta et al, 2009). At the same time it has been observed that at pH 7, 45.8% recovery of mercury is possible from Charcoal Immobilized Papain (CIP)-mercury complex, which means that there is always a possibility of leakage of mercury ions during an actual continuous process or during any neutral wash.…”