Radiation-grafted copolymers for separation and purification purposes: Status, challenges and future directions

A horseradish peroxidase immobilized radiation grafted polymer matrix: a biocatalytic system for dye waste water treatment

A single step-environment friendly-water based-radiation grafting process was used to fabricate an epoxy functionalized polymer support for one step-covalent immobilization of enzyme HRP in ambient conditions, and tested for dye waste water treatment.

San copolymer membranes with ion exchangers for Cu(II) removal from synthetic wastewater by electrodialysis

Heterogeneous membranes were obtained by using styrene-acrylonitrile copolymer (SAN) blends with low content of ion-exchanger particles (5wt.%). The membranes obtained by phase inversion were used for the removal of copper ions from synthetic wastewater solutions by electrodialytic separation. The electrodialysis was conducted in a three cell unit, without electrolyte recirculation. The process, under potentiostatic or galvanostatic control, was followed by pH and conductivity measurements in the solution. The electrodialytic performance, evaluated in terms of extraction removal degree (rd) of copper ions, was better under potentiostatic control then by the galvanostatic one and the highest (over 70%) was attained at 8V. The membrane efficiency at small ion-exchanger load was explained by the migration of resin particles toward the pores surface during the phase inversion. The prepared membranes were characterized by various techniques i.e. optical microscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis and differential thermal analysis and contact angle measurements.

Celebrating Soft Matter's 10th Anniversary: chain configuration and rate-dependent mechanical properties in transient networks

Numerical solution of a coupled set of Smoluchowski convection-diffusion equations of associating polymers modelled as finitely extensible dumbbells enables computation of time-dependent end-to-end distributions for bridged, dangling, and looped chains in three dimensions as a function of associating end-group kinetics. Non-monotonic flow curves which can lead to flow instabilities during shear flow result at low equilibrium constant and high association rate from two complementary phenomena: a decrease in the fraction of elastically active chains with increasing shear rate and non-monotonic extension in the population of elastically active chains. Chain tumbling leads to reformation of bridges, resulting in an increased fraction of bridged chains at high Deborah number and significant reduction in the average bridge chain extension. In the start-up of steady shear, force-activated chain dissociation and chain tumbling cause both stress overshoot and stress ringing behaviour prior to reaching steady state stress values. During stress relaxation following steady shear, chain kinetics and extension mediate both the number of relaxations and the length of time required for system relaxation. While at low association rate relaxation is limited by the relaxation of dangling chains and the rate of dangling chain formation, at high association rate coupling of dangling and bridged chains leads to simultaneous relaxation of all chains due to a dynamic equilibrium between dangling and bridged states.

Macroporous monoliths for trace metal extraction from seawater

Macroporous monolith adsorbents were prepared from acrylonitrile and crosslinker based on cryogel methods and were tested for uranium seawater mining.

Tuning N-methyl-d-glucamine density in a new radiation grafted poly(vinyl benzyl chloride)/nylon-6 fibrous boron-selective adsorbent using the response surface method

A new adsorbent containing boron-selective groups was prepared by radiation-induced grafting of vinyl benzyl chloride (VBC) onto nylon-6 fibers followed by functionalisation with N-methyl-d-glucamine (NMDG).