High levels of indoor air CO2 in commercial buildings can lead to various health effects, commonly known as sick building syndrome. Passive control of indoor air CO2 through solid adsorbents incorporated into the paint offers a high potential to handle CO2 without utilizing much energy. This study focuses on incorporating silica-supported aminopolymers into a polyacrylic-based latex that could be used as a buffer material for the passive control of CO2 in enclosed environments. To maximize the effect of the pigment (adsorbent), paints were all prepared at critical pigment volume concentration (CPVC) levels. CO2 at 800 and 3000 ppm were used to asses both low and high level contaminations. The removal efficiency of the surface coatings was evaluated within typical time frames (10 h for adsorption and desorption). Our laboratory-scale chamber results indicated that the silica-tetraethylenepentamine-based paint with 70 wt % loading exhibits the best adsorption performance, comparable to that of the powder-based sorbent, with only a ∼20% decrease in the adsorption efficiency. Our results also revealed that the optimization of paint formulation is critical in passively controlling indoor air CO2. The findings of this study highlight the potential of amine-based adsorbents as pigments in high PVC paints for indoor CO2 control in commercial buildings.

Removal of dyes through adsorption from wastewater has gained substantial interest in recent years, especially in development of hydrogel based adsorbents, owing to their easy use and economical nature. The aim of the present study was to design a super-adsorbent hydrogel based on sodium styrenesulfonate (NaSS) monomer for removal of dyes like methylene blue (MB). NaSS displays both an aromatic ring and strongly ionic group in its monomer structure that can enhance adsorption capacity. Poly(sodium styrenesulfonate-co-dimethylacrylamide) hydrogels were prepared by solution free radical polymerization using gelatin methacryloyl (GelMA) as crosslinker, creating a highly porous, three-dimensionally crosslinked polymer network contributing to higher swelling ratios of up to 27,500%. These super-adsorbent hydrogels exhibited high adsorption capacity of 1270 mg/g for MB adsorption with above 98% removal efficiency. This is the first report for such a high adsorption capacity for dye absorbance for NaSS-based hydrogels. Additionally, the adsorption kinetics using a pseudo-first-order and the Freundlich adsorption isotherm models for multilayer, heterogeneous adsorption processes has been reported. The adsorbents’ reusability was confirmed through 4 repeated cycles of desorption-adsorption. The results discussed herein illustrate that NaSS based chemistries can be used as an efficient option for removal of organic dyes from contaminated wastewater.

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Summary Preformed particle gels (PPGs) are 3D, crosslinked, dried polymer particles that can swell to several hundred times on contact with formation water. PPGs have been used extensively to control water production problems in reservoirs with conformance problems. The current state-of-the-art PPGs are polyacrylamide-based hydrogel compositions which lack long-term thermal stability under high-temperature and -salinity conditions. There are many oil reservoirs across the globe exhibiting conditions of temperatures higher than 120°C with high salinity. A novel ultrahigh-temperature-resistant PPG composition (DMA-SSS PPG) was designed to fill up the technology gap between existing polyacrylamide-based PPG technology that degrades readily over 110°C temperatures. DMA-SSS PPG exhibited excellent thermal stability for greater than 18 months in North Sea formation and formation water environments at 130°C. DMA-SSS PPG described herein showed swelling capacities of up to 30 times in different salinity North Sea brines. DMA-SSS PPG’s physiochemical properties like swelling, swelling rate, and rheological behavior were studied as a function of temperature and salinity. DMA-SSS PPGs showed excellent elastic modulus (G’) of about 3200 Pa in formation water of 90% water content. Thermostability of DMA-SSS PPGs was assessed at 130 and 150°C in North Sea brines with different salinity conditions. DMA-SSS PPGs proved to be stable for more than 18 months without losing molecular integrity. Thermostability was further confirmed through different metrics such as cross-polarization magic angle spinning carbon-13 nuclear magnetic resonance (CPMAS 13C NMR), thermogravimetric analysis (TGA), and morphology. Laboratory coreflood experiments were performed to demonstrate the plugging efficiency of open fractures and effectiveness in reducing the permeability. DMA-SSS PPG comprehensive evaluation confirms its novelty for excellent hydrothermal stability, thus can be used to control water production problems for mature reservoirs exhibiting conditions of high salinity and high temperature.