LbL Fabricated Poly(Styrene Sulfonate)/TiO₂Multilayer Thin Films for Environmental Applications

Abstract

Fabrication of multilayer ultrathin composite films composed of nanosized titanium dioxide particles (P25, Degussa) and polyelectrolytes (PELs), such as poly(allyl amine hydrochloride) (PAH) and poly(styrene sulfonate sodium salt) (PSS), on glass substrates using the layer-by-layer (LbL) assembly technique and its potential application for the photodegradation of rhodamine B under ultraviolet (UV) irradiation has been reported. The polyelectrolytes and TiO(2) were deposited on glass substrates at pH 2.5 and the growth of the multilayers was studied using UV/vis spectrophotometer. Thickness measurements of the films showed a linear increase in film thickness with increase in number of bilayers. The surface microstructure of the thin films was characterized by field emission scanning electron microscope. The ability of the catalysts immobilized by this technique was compared with TiO(2) films prepared by drop casting and spin coating methods. Comparison has been made in terms of film stability and photodegradation of rhodamine B. Process variables such as the effect of surface area of the multilayers, number of bilayers, and initial dye concentration on photodegradation of rhodamine B were studied. Degradation efficiency increased with increase in number of catalysts (total surface area) and bilayers. Kinetics analysis indicated that the photodegradation rates follow first order kinetics. Under maximum loading of TiO(2), with five catalyst slides having 20 bilayers of polyelectrolyte/TiO(2) on each, 100 mL of 10 mg/L dye solution could be degraded completely in 4 h. The same slides could be reused with the same efficiency for several cycles. This study demonstrates that nanoparticles can be used in wastewater treatment using a simple immobilization technique. This makes the process an attractive option for scale up.

Photocatalytically Active Polyelectrolyte/Nanoparticle Films for the Elimination of a Model Odorous Gas

“…3 g Á L À1 ) for 20 min followed by rinsing with ultrapure water (3 Â 3 min). While similar Aeroxide TiO 2 P25 rich LbL films were already described, [25] this first layer of PEI helps to promote the adhesion of the film on the reactor surface and to prevent delamination. Then, the PEI-coated substrates were immersed in an aqueous solution of poly-(sodium 4-styrene sulfonate) (PSS, M w % 70 000 g Á mol…”

“…For example, polyelectrolyte multilayers containing commercially available Aeroxide TiO 2 P25 were used to degrade rhodamine B. [25] In the last few years, progress has also been made in the field of gas phase PCO reactions. One of the primary reasons that gas phase PCO reactions are being studied is for the use of such catalytic systems in the destruction of chemical warfare agents and air pollutants.…”

Bifunctional ultraviolet/ultrasound responsive composite TiO2/polyelectrolyte microcapsules

“…TiO 2 has been widely used as a UV-absorbing agent for environmental applications and here they were used to absorb UV light to increase the permeability of polymer capsules. 34,35 The UV absorbance spectra of the composite capsules were measured by means of UV/Vis spectroscopy, as given in Figure 4. The TiO 2 /PE composite capsules showed two absorbance peaks with a wide tailing area up to 700nm whereas no obvious absorbance peak was found for PAH/PSS capsules without TiO 2 incorporation.…”

Smart Membrane Surfaces: Wettability Amplification and Self‐Healing

“…Recently, the catalytic activity of poly(allyl amine hydrochloride) (PAH) and poly(styrene sulfonate sodium salt) (PSS) multilayers containing TiO 2 has been evaluated for the degradation of Rhodamine B dye under UV irradiation time of 4 h [79].…”