Cassia marginata

Cassia marginata syn Cassia roxburghii [93] is a large sized Indian tree having cylindrical and indehiscent long pods with many seeds and a black cathartic pulp which is used as a horse medicine. Cassia marginata seed gum-graft-poly(methylmethacrylate) (CM-g-PMMA) has been synthesized and evaluated as biosorbent in the removal of Cr(VI) from the synthetic solutions and real wastewater. 

In conventional grafting procedures redox initiators are commonly used to initiate the grafting reactions. These initiators produce ions in the reaction medium which may be adsorbed at the copolymer surface to some extent. To avoid this, there has been recent interest in the use of microwave induced grafting reactions. Using microwave irradiation, methylmethacrylate (MMA) has been efficiently grafted onto Cassia marginata seed gum in the absence of 

Changing various reaction parameters, graftcopolymer samples of different performances have been obtained. The optimum % grafting (270 %G) and % efficiency (59% E) sample is produced when 4g/L CM gum and 18.0 xlO M methylmethacrylate is exposed for 0.66 min to 40% microwave power. 

Water solubility of microwave synthesized copolymer samples decreases with an increase in % grafting, and the sample obtained under optimum grafting conditions shows complete water insolubility and has been used in the Cr(VI) removal from the aqueous solution. The efficacy of the graft copolymer in Cr(VI) removal increases with an increase in the grafting ratio due to the availability of the additional binding sites at the PMMA grafts in the copolymer. 

Maximum Cr(VI) removal has been observed at pH 1.0 and Cr(Vl) removal by CM-g-PMMA decreases with the variation of pH 1.0-10.0 at 100 mg/L initial Cr(VI) concentration. Total chromium in the equilibrium solution (after the adsorption was detected by the Diphenylcarbazide (DPC) method) indicates that some Cr(Vl) converts to Cr(III) during the adsorption and remains in the equilibrium solution along with the remaining Cr(Vl). Krishnani et al. [96] have made a similar observation for the adsorption of chromium on Ugnocellulosic substrates. At a low pH, lignin reportedly reduces hexavalent chromium into Cr(III), which is subsequently adsorbed contrary to the adsorption by CM-g-PMMA where the copolymer adsorbed chromium mainly as Cr(VI), while Cr(IlI), that is generated from the reduction of the Cr(Vl) at acidic pH still remains in solution. However, at pH 10 a negligible conversion of Cr (VI) to Cr(III) is reported. 

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Rhamnosyl(l —> 2)glucosyl(l 6)galactoside Cassia marginata stems Leguminosae 189... 

Singh V, Kumari PL, Tiwariy A et al (2007) Alumina supported synthesis of cassia marginata gum-g-poly(acrylonitrile) under mioowave irradiation. Polym Adv Technol 18 379-385... 

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