DOI: 10.5061/dryad.n2z34tmtq
title: Data from: Spirobifluorene-based polymers of intrinsic microporosity for the adsorption of methylene blue from wastewater: effect of surfactants

description: Owing to their high surface area and superior adsorption properties,
 spirobifluorene PIMs namely, PIM-SBF-Me (methyl) and PIM-SBF-tBu
 (tert-butyl) were used for the first time for the removal of methylene
 blue (MB) dye from wastewater. Spirobifluorene PIMs are known to have
 large surface area (can be up to 1100 m2/g) and have been previously used
 mainly for gas storage applications. Dispersion of the polymers in aqueous
 solution was challenging due to their extreme hydrophobic nature leading
 to poor adsorption efficiency of MB. For this reason, cationic (CPC),
 anionic (SDS) and nonionic (Brij-35) surfactants were utilized and tested
 with the aim of enhancing the dispersion of the hydrophobic polymers in
 water and hence improving the adsorption efficiencies of the polymers. The
 effect of surfactant type and concentration was investigated. All
 surfactants offered a homogenous dispersion of the polymers in the aqueous
 dye solution, however, the highest adsorption efficiency was obtained
 using an anionic surfactant (SDS) and this seems due to the predominance
 of electrostatic interaction between its molecules and the positively
 charges dye molecules. Furthermore, the effect of polymer dosage and
 initial dye concentration on MB adsorption were also considered. The
 kinetic data for both polymers were well described by pseudo-second-order
 model, while Langumir model better simulated the adsorption process of MB
 dye on PIM-SBF-Me and Freundlich model was more suitable for PIM-SBF-tBu.
 Moreover, the maximum adsorption capacities recorded were 84.0 and 101.0
 mg/g for PIM-SBF-Me and PIM-SBF-tBu, respectively. Reusability of both
 polymers was tested by performing three adsorption cycles and the results
 substantiate that both polymers can be effectively reused with
 insignificant loss of their adsorption efficiency (%AE). These preliminary
 results suggested that incorporation of a surfactant to enhance the
 dispersion of hydrophobic polymers and adsorption of organic contaminants
 from wastewater is a simple and cost-effective approach that can be
 adapted for many other environmental applications.
description: The
 removal of MB from water using both PIM-SBF-Me and PIM-SBF-tBu was
 evaluated by performing a series of experiments. Initially, 1-10 mg of
 both polymers was added to 10 mL of 5.0–25.0 mg/L MB solution in the
 presence of a surfactant. After mixing for 100 min, the remaining
 concentration of MB in the solution was determined by measuring the change
 λ<sub>max</sub> = 662 nm in a quartz cuvette using UV-Vis
 spectrometer. The adsorption
 efficiency (AE) for MB on both polymers was estimated using
 Equation 1 <sup>8</sup>: %AE =<i>
 </i><i>(</i><i>C</i><sub><i>o</i></sub><i>-</i><i>C</i><sub><i>t</i></sub><i>)</i><i>C</i><sub><i>o</i></sub><i>×</i><i> 100</i>                                                                                                    <b>(1)</b> Where C<sub>o</sub> and C<sub>t</sub> represent the initial MB concentration and the MB concentration at time t (mg/L), respectively. The amount of MB adsorbed per unit mass of PIM-SBF-Me and PIM-SBF-tBu was calculated using Equation 2: q<sub><i>t</i></sub>=(<i>C</i><sub><i>0</i></sub>-<i>C</i><sub><i>t</i></sub>)Vm <b>   </b>                                                                                                              <b>(2)</b> Where V and m the volume of solution (L) and the mass of the polymers added to the MB solution (g), respectively. At equilibrium, the equation can be modified: q<sub><i>eq</i></sub>=(<i>C</i><sub><i>0</i></sub>-<i>C</i><sub><i>eq</i></sub>)Vm <b>                                                                                   </b>                          <b>(3)</b> Where q<sub>eq</sub> and C<sub>eq</sub> are the amount of MB adsorbed per gram of the polymer (mg/g) and the concentration of MB at equilibrium (mg/L), respectively. All adsorption isotherms and kinetic measurements were performed using the optimized conditions of adsorbent dosage and initial dye concentration. In brief, the optimum amount of the polymer was added into 10 mL of MB dye solution. The mixture was magnetically stirred, and the concentration of dye in the solution was determined at definite time intervals and analysed spectrophotometrically without filtration.
description: The instrumentation used for the characterisation for polymers
 are reported in the paper  Bezzu, C.G., Carta, M.,
 Ferrari, M.-C., Jansen, J.C., Monteleone, M., Esposito, E., Fuoco, A.,
 Hart, K., Liyana-Arachchi, T., Colina, C.M., 2018. The synthesis,
 chain-packing simulation and long-term gas permeability of highly
 selective spirobifluorene-based polymers of intrinsic microporosity.
 Journal of Materials Chemistry A 6(22), 10507-10514.
 Additionally, to assess the adsorption and its kinetics UV-Vis
 analysis was carried out using Agilent Cary 5000 Scan UV-Vis-near-infrared
 spectrometer. The adsorption of MB on PIM-SBF-Me and PIM-SBF-tBu was
 investigated using Jasco FTIR-630 FTIR spectroscopy. The polymer,
 surfactant micelles and polymer-micelle size distribution was determined
 by photon correlation spectroscopy using a Zetasizer Nano ZS (Malvern
 Instruments, UK), with a frequency doubled DPSS Nd: YAG laser with output
 power of 50 mW operating at a wavelength of 532 nm and an angle of 175.
 All the measurements were performed at room temperature and for each
 sample three measurements were carried out in disposable cuvettes. The
 refractive index and viscosity of the solvent were taken into
 consideration when measurements were taken.