Sandipta Ghosh

Flocculation properties of polyacrylamide grafted carboxymethyl guar gum (CMG-g-PAM) synthesised by conventional and microwave assisted method

A novel polymeric flocculant based on polyacrylamide grafted carboxymethyl guar gum (CMG-g-PAM) has been synthesised by grafting polyacrylamide chains onto CMG backbone using conventional redox grafting and microwave assisted grafting methods. Under optimum grafting conditions, 82% and 96% grafting efficiencies have been observed in case of conventional and microwave assisted methods respectively. The optimum sample has been characterized using viscometry, spectroscopic analysis, elemental analysis, molecular weight and radius of gyration determination. The flocculation characteristics of grafted and ungrafted polysaccharides have been evaluated in kaolin suspension, municipal sewage wastewater and decolourization efficiency of a dye solution (methylene blue). It is evident from results that CMG-g-PAM synthesised by microwave assisted grafting method is showing best flocculation characteristics.

Novel biodegradable polymeric flocculant based on polyacrylamide-grafted tamarind kernel polysaccharide.

Novel biodegradable polymeric flocculants were produced by conventional redox grafting, microwave-initiated and microwave-assisted grafting of acrylamide to tamarind kernel polysaccharide (TKP). The graft copolymers were characterized by viscometry, elemental analysis, molecular weight determination using SLS analysis, and NMR spectroscopy. The flocculation efficiency of the grafting products in kaolin suspension, municipal sewage wastewater and textile industry wastewater was primarily dependent on the length of the grafted polyacrylamide chain. The flocculant obtained by microwave-assisted grafting method was superior to TKP and polyacrylamide-based commercial flocculant (Rishfloc 226 LV) in flocculation tests.

Study of algal biomass harvesting using cationic guar gum from the natural plant source as flocculant

Microalgae are small in size with negatively charged surface. They are usually stable in suspension culture and hard to flocculate. The present work emphasizes on the synthesis of cationic guar gum (CGG) by the introduction of quaternary amine groups onto the backbone of guar gum (GG) from N-(3-chloro-2-hydroxypropyl) trimethyl ammonium chloride (CHPTAC). The optimal dosage of the synthesized cationic guar gum is used to flocculate two different green algae viz. Chlorella sp. CB4 and Chlamydomonas sp. CRP7.

Microwave assisted synthesis of polyacrylamide grafted dextrin (Dxt-g-PAM): Development and application of a novel polymeric flocculant.

An efficient polymeric flocculant was synthesized by microwave assisted grafting of polyacrylamide to dextrin. By varying the reaction conditions, various grades of graft copolymers were synthesized to obtain the optimized one. Viscometry, elemental analysis, FTIR spectroscopy, (13)C NMR spectroscopy, determination of molecular weight and radius of gyration using SLS analysis, thermal analysis and SEM analysis were employed to confirm that polyacrylamide has been grafted onto the dextrin backbone. The flocculation efficiency of the grafted products in kaolin suspension was dependent on the molecular weight, radius of gyration and length of the grafted polyacrylamide chains. The flocculant obtained by microwave assisted grafting method was superior to dextrin and polyacrylamide-based commercial flocculant (Rishfloc 226 LV) in flocculation tests.

Cationic tamarind kernel polysaccharide (Cat TKP): a novel polymeric flocculant for the treatment of textile industry wastewater.

Synthesis of cationic tamarind kernel polysaccharide (Cat TKP), its detailed physicochemical characterization and application as an efficient flocculant for the treatment of textile industry wastewater have been investigated. N-3-Chloro-2-hydroxypropyl trimethyl ammonium chloride (CHPTAC) was used as a cationic reagent to introduce quaternary amine groups onto the backbone of tamarind kernel polysaccharide (TKP). Various grades were synthesized to obtain the optimized one. Effect of reaction parameters onto the degree of cationization has also been investigated. The synthesized polymers were characterized by various macromolecular characterization techniques, which confirm that cationization does take place. Afterwards, the applicability of TKP and various grades of Cat TKPs as flocculants for the treatment of textile industry wastewater was investigated. The flocculation experiments showed that TKP alone contributes little to the flocculation. However, cationic TKP led to significant improvement as flocculant for the treatment of textile industry wastewater. The best performing Cat TKP (i.e. Cat TKP 3) was thereafter compared with a commercial flocculant, which is cationic in nature. It has been observed that Cat TKP 3 surpasses the flocculation efficiency over commercial flocculant.

Study of algal biomass harvesting through cationic cassia gum, a natural plant based biopolymer

Green unicellular microalgae have a capacity to entrap CO2 to increase their biomass through photosynthesis and are important for the value added product. The presence of COOH and NH2 groups are responsible for imparting negative zeta value. The present work emphasizes on the synthesis of cationic cassia (CCAS) by the insertion of quaternary amine groups onto the backbone of cassia (CAS) from N-3-Chloro-2-hydroxypropyl trimethyl ammonium chloride (CHPTAC) which was further characterized via FTIR, SEM, elemental analysis and intrinsic viscosity. The optimal dosage of the synthesized cationic cassia is used to flocculate two different green fresh water algae viz. Chlamydomonas sp. CRP7 and Chlorella sp. CB4 were evaluated. 80 and 35 mg L(-1) was optimized dose for dewatering of above algae, respectively.

Modified tamarind kernel polysaccharide: a novel matrix for control release of aspirin

pH dependent hydrogels of modified tamarind kernel polysaccharide (TKP) were synthesized by grafting with polyacrylamide chains on TKP backbone in presence of microwave irradiation and initiator. The present study is carried out to design oral controlled drug delivery systems for aspirin using synthesized hydrogels as carrier in form of tablets. TKP-g-PAM based hydrogels show significant enhancement for control release of aspirin. Release behavior of aspirin has been evaluated using USP type I apparatus in 900 mL of buffer solutions (pH 1.2, 6.8, 7.4), maintained at 37°C at 100 rpm. It is observed that with increase in percentage of grafting (% G), swelling of matrices increases whereas erosion and rate of drug release decrease. The effect of % G onto t50 value (time taken for release of 50% drug) has also been discussed. The release characteristics from the matrices under study show non-Fickian diffusion mechanism, suggesting the controlled release of aspirin.

High performance polymeric flocculant based on hydrolyzed polyacrylamide grafted tamarind kernel polysaccharide (Hyd. TKP-g-PAM).

A high performance anionic flocculant was synthesized by partial alkaline hydrolysis of polyacrylamide grafted tamarind kernel polysaccharide. Various macromolecular characterizations were employed to confirm that partial alkaline hydrolysis of grafted polyacrylamide chains does take place. The flocculation characteristics of the hydrolyzed and unhydrolyzed grafted products were carried out in kaolin suspension and municipal sewage wastewater and it has been found that hydrolyzed product outperforms the unhydrolyzed grafted TKP.