The amino-functionalized nanosilica/polymer hybrid systems have better salt tolerance and EOR performance than unmodified nanosilica polymer hybrid systems.

In this paper, a novel method for preparing nanoparticle-polymer hybrid adsorbent was established. Laponite was dispersed in distilled water to form Laponite nanoparticles. These nanoparticles were pre-adsorbed by 2-acrylamido-2-methylpropane-sulfonic acid (AMPS) to improve their dispersion stability in chitosan solution. The nanoparticle-polymer hybrid adsorbent was prepared by copolymerization of chitosan, acrylamide, acrylic acid, AMPS, and Laponite nanoparticles. Four adsorbents were obtained and characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller adsorption (BET). Additionally, the uptake capacities of Cu²⁺ using different samples were studied. Compared to the adsorbent without chitosan and Laponite components, the maximum uptake of the hybrid adsorbent increased from 0.58 to 1.28 mmol·g⁻¹ and the adsorption equilibrium time of it decreased from more than 75 min to less than 35 min, which indicated that the addition of chitosan and Laponite could greatly increase the adsorption rate and capacity of polymer adsorbent. The effects of different experimental parameters—such as initial pH, temperature, and equilibrium Cu²⁺ concentration—on the adsorption capacities were studied. Desorption study indicated that this hybrid adsorbent was easy to be regenerated.

A series of chitosan and Laponite based nano-composite adsorbents, which showed an excellent performance for fast and efficient removal of Cd(II), methylene blue (MB) and Congo red (CR) from aqueous solution, were prepared. In the adsorbent, with the increase of Laponite component, the surface area increased from 44.69 m²g^-1to 64.58 m²g^-1. As a result, the adsorption rates were enhanced by increasing Laponite component. The adsorption capacities for Cd(II) and MB increased with increasing Laponite component due the cationic characteristic of two pollutants, and the opposite result was found for the removal of CR. The impacts of some factors, e.g. solution pH, temperature, pollutant concentration and salt, on the adsorption capacity were investigated. Additionally, this adsorbent could be effectively regenerated by dilute HCl solution after the adsorption of Cd(II), and the mixture of methanol and acetic acid was a suitable eluent after the adsorption of two dyes.