Gautam Sen

Microwave assisted synthesis of polyacrylamide grafted starch (St-g-PAM) and its applicability as flocculant for water treatment.

Polyacrylamide grafted starch (St-g-PAM) was made by a novel method of synthesis, involving combination of microwave radiation and a chemical free radical initiator (ceric ammonium nitrate) to initiate grafting reaction. This method (microwave assisted synthesis) is quick, highly reliable, reproducible and yields high quality product as compared to the conventional method (which uses a chemical free radical initiator alone to initiate the grafting reaction).The St-g-PAM grades synthesized were characterized by various physicochemical techniques. Further, its application as flocculant for wastewater treatment was investigated.

Microwave initiated synthesis of polyacrylamide grafted guar gum (GG-g-PAM)—Characterizations and application as matrix for controlled release of 5-amino salicylic acid

This paper details the study of applicability of microwave initiated synthesized polyacrylamide grafted guar gum (GG-g-PAM) as matrix for controlled release of 5-amino salicylic acid (a drug used for the treatment of ulcerative colitis). In vitro release of this drug from various grades of GG-g-PAM has been studied by USP dissolution method (paddle type). The effect of percentage grafting on the rate of drug release has been investigated. The power of the microwave oven and other factors being kept constant, the percentage grafting in turn is dependent on the net time of exposure to microwave irradiation; thus a correlation can be drawn between net time of irradiation and rate of drug release (from the matrix). This holds the promise of a tailor-made matrix, with the rate of drug release being precisely programmed at the molecular level. Further, the drug release study was carried out in different pH medium, to investigate the possibility of pH triggered release for colon targeted drug delivery (where the pH is alkaline).

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 based synthesis of polymethyl methacrylate grafted sodium alginate: its application as flocculant.

Polymethyl methacrylate grafted sodium alginate (SAG-g-PMMA) was synthesized by microwave assisted method. The grafting of the PMMA chains on the polysaccharide backbone was confirmed through intrinsic viscosity study, FTIR spectroscopy, elemental analysis (C, H, N, O and Na), SEM and TGA study. The intrinsic viscosity of sodium alginate appreciably improved on grafting of PMMA chains, thus resulting grafted product with potential application as superior viscosifier. Further, flocculation efficacy of the graft copolymer was studied in coal fine suspension through jar test procedure, toward possible application as flocculant.

A novel polymeric flocculant based on polyacrylamide grafted inulin: aqueous microwave assisted synthesis.

Polyacrylamide grafted inulin (In-g-PAM) was synthesized via aqueous microwave assisted method (using ceric ammonium nitrate in synergism with microwave in aqueous medium). The intended grafting of the PAM chains on polysaccharide backbone was confirmed through standard physicochemical characterization techniques, namely intrinsic viscosity measurement, Fourier transform infrared (FTIR) spectroscopy, elemental analysis (C, H, N and O), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) studies. Flocculation efficacy of various grades of synthesized grafted product was studied in coal fines suspension, in relation to inulin (parent polysaccharide). This was done utilizing jar test and settling test procedure, towards possible application as a flocculant for coal washery effluents.

Synthesis, characterization and applications of polymethylmethacrylate grafted psyllium as flocculant

Polymethylmethacrylate grafted psyllium (Psy-g-PMMA) was synthesized by microwave assisted method. The grafting of the PMMA chains on the psyllium backbone was confirmed through the study of intrinsic viscosity, FTIR spectroscopy, elemental analysis, SEM and number average molecular weight (Mn). The intrinsic viscosity and number average molecular weight (Mn) of psyllium appreciably improved on grafting of PMMA chains. Further, flocculation efficacy of the graft copolymer was studied in kaolin suspension through jar test procedure, towards possible application as flocculant.

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.

Carboxymethyl inulin: A novel flocculant for wastewater treatment

Carboxymethyl inulin (CMI) has been synthesized by incorporation of carboxymethyl groups in the inulin framework; by reacting inulin with sodium salt of monochloro acetic acid (SMCA) in presence of sodium hydroxide. The resulting carboxymethylated product, with different degrees of substitution, has been confirmed through various physicochemical characterization techniques, such as intrinsic viscosity measurement, elemental analysis (C, H, N and O), FTIR spectroscopy, thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) studies. Flocculation efficacy of various grades of CMI, have been studied in kaolin suspension and then in municipal wastewater, in relation to inulin (parent polysaccharide). This has been done utilizing jar-test procedure towards possible application as a flocculant for waste water treatment.

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.