Contaminated water and scarcity of clean water are serious global environmental concerns. Elimination of hazardous organic/inorganic contaminants from water/sewages is essential and demands immediate attention in order to protect pure water resources. Adsorptive decontamination of aqueous pollutants is widely accepted technology owing to its simple handling, higher efficiency and economic viability. Functionalized natural polymeric materials such as cellulose, biomass, starch, proteins, and biochar have been considered as highly effective adsorbents for the elimination of aqueous pollutants, in particular heavy metal ions, textile dyes, pharmaceuticals and hazardous organic compounds. Biobased hydrogels fabricated via introduction of oxygen, nitrogen and sulphur comprising groups and inorganic fillers (graphene, clay, carbon nanotubes, etc.) are attractive materials owing to their distinctive physicochemical properties, cost-effectiveness, ease of fabrication and operation, large specific surface area and porosity, and easy reusability. Functional biobased hydrogels showed superior adsorption performance for cationic contaminants via electrostatic and hydrogen (H)-bonding interactions. This review summarizes state-of-the-art biobased hydrogels including their intrinsic properties, previous and recent advances and future tactics for their use in wastewater treatment applications. Fabrication methods and properties of modified biobased hydrogels and their adsorption characteristics are specially focused. Development of biobased hydrogels with desirable properties such as three-dimensional (3D) microstructure, high porosity and surface area and multifunctionality is a potential way to fulfill the expanding demands of wastewater treatment at an industrial scale. The current position of invention and utilization of biobased hydrogels in wastewater treatment is reviewed without ignoring iconic studies that have advanced this area of research to the current stage. Eventually, future perspectives for the development of advanced biobased hydrogels to overcome separation problems and move towards new technological aspects are also described.

A full set of flexible force field parameters for ZIF-8 is presented, based on the AMBER, UFF parameters and the partial charges computed by the density-derived electrostatic and chemical charge method (DDEC). The parameters for the 2-methyl imidazole (MeIM) ring are adopted from the AMBER force field, while the van der Waals (VDW) parameters for organic linkers and metal centers were determined by rescaling the UFF parameters as ε = 0.635ε_UFF and σ = 1.0σ_UFF to fit the CH₄ adsorption isotherms obtained by Grand Canonical Monte Carlo (GCMC) simulations with the force field parameters to the experimental ones. The CH₄ adsorption isotherms on four different structures of ZIF-8 at 298 K obtained by GCMC simulations are compared with the experimental data. The results show that the simulated CH₄ adsorption isotherms on the ZIF-8 structure reported from the Cambridge Crystallographic Data Centre (CCDC) are closest to the ones on the ZIF-8 structure from the report of Moggach et al. To test our model, adsorption isotherms of CH₄, H₂, CO₂ and N₂ at different temperatures were computed using GCMC simulations, and the results were found to be in a good agreement with the experimental data. In the case of H₂, the equilibrium configurations obtained by GCMC simulations were statistically analyzed with ad hoc code to get probability density distribution profiles. These profiles were transformed to visual slice images, which indicate that the preferential adsorption sites of H₂ molecules in ZIF-8 are located close to the MeIM rings, where the host–guest VDW or electrostatic interactions are maximal, as revealed by the potential energy surfaces (PES). In addition, these force field parameters were confirmed to well reproduce the ZIF-8 structural properties including lattice constants, bond lengths and angles over a wide range of temperatures. The self-diffusivities at the specific loadings of adsorbed gases (CH₄, H₂ and CO₂) in ZIF-8 were calculated by the mean squared displacement (MSD) method. It was found that our self-diffusivities of H₂ are slightly higher than the ones in the literature, and our self-diffusivity of CO₂ is as about three times as the one in the literature, due to the different partial charges and the effect of different force field parameters on framework shape and flexibility in our simulations.

Selenium is an important element for human’s health, small size is very helpful for Se nanoparticles to be absorbed by human's body. Here, we present a facile approach to fabrication of small selenium nanoparticles (Nano-Se) as well as nanorods by dissolving sodium selenite (Na2SeO3) in glycerin and using glucose as the reduction agent. The as-prepared selenium nanoparticles have been characterized by X-ray diffraction (XRD), UV-Vis absorption spectroscopy and high resolution transmission electron microscope (HRTEM). The morphology of small Se nanoparticles and nanorods have been demonstrated in the TEM images. A small amount of 3-mercaptoproprionic acid (MPA) and glycerin play a key role on controlling the particle size and stabilize the dispersion of Nano-Se in the glycerin solution. In this way, we obtained very small and uniform Se nanoparticles; whose size ranges from 2 to 6 nm. This dimension is much smaller than the best value (>20 nm) ever reported in the literatures. Strong quantum confinement effect has been observed upon the size-dependent optical spectrum of these Se nanoparticles.