title: Synthesis and application of calix[4]arene based resin for the removal of azo dyes.
abstract: The present study describes a novel synthetic method for the immobilization of calix[4]arene (II) onto the surface of modified Amberlite XAD-4 resin (4), which does not require the derivatization of calixarene moiety. The novel calix[4]arene based resin (C4 resin) 5 was used as sorbent for the removal of azo dyes. Batch-wise sorption study was carried out and observed that the C4 resin (5) is more effective as compared to compound II as well as pure Amberlite XAD-4 resin (1) to remove the selected dyes [i.e. Reactive Black-5 (RB-5), Reactive Red-45 (RR-45) and Congo Red (CR)]. The effect of sorbent dosage and pH on % sorption was studied. During the extraction process, various kinds of interactions such as electrostatic repulsion, deprotonation of the hydroxyl groups of C4 resin, dissociation of reactive dyes into anions/cations and structural variations were monitored and found that they are highly pH dependent.
authors.affiliation: National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080, Pakistan.
authors.forename: Muhammad Afzal
authors.initials: MA
authors.lastname: Kamboh
authors.forename: Imam Bakhsh
authors.initials: IB
authors.lastname: Solangi
authors.forename: S T H
authors.initials: ST
authors.lastname: Sherazi
authors.forename: Shahabuddin
authors.initials: S
authors.lastname: Memon
mesh_terms: D000327:Adsorption; D001391:Azo Compounds / Q000737:chemistry / Q000302:isolation & purification*; D047250:Calixarenes / Q000737:chemistry*; D004396:Coloring Agents / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste; D008956:Models, Chemical; D011137:Polystyrenes / Q000737:chemistry*; D011145:Polyvinyls / Q000737:chemistry*; D012117:Resins, Synthetic; D017550:Spectroscopy, Fourier Transform Infrared; D055672:Static Electricity; D013696:Temperature; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*
chemical_list: D001391:Azo Compounds; D004396:Coloring Agents; D007220:Industrial Waste; D011137:Polystyrenes; D011145:Polyvinyls; D012117:Resins, Synthetic; D014874:Water Pollutants, Chemical; D047250:Calixarenes; C012101:XAD-4 resin; C046797:amberlite