Estimation and statistical analysis of model parameters using sequential Monte Carlo for phenol and p-cresol separation.

Model-based design and optimization methods facilitate industrial applications of chromatographic separations. The uncertainty of the model parameters must be quantified to ensure robust design and control. In this study, we propose an approach using the sequential Monte Carlo (SMC) method based on the Bayesian principle to estimate the uncertainty of the parameters. The linear driving force model for separation of phenol and p-cresol was considered as an example. By comparing different injection tests, we confirmed the necessity of pulse injection and breakthrough experiments to estimate parameters with sufficient accuracy and precision. We also found that modeling observation errors carefully is critical to obtain reasonable estimation.

One-Pot Synthesis of Lamellar Fe-Cu Bimetal-Decorated Reduced Graphene Oxide and Its Enhanced Removal of Cr(VI) from Water.

Hexavalent chromium (Cr(VI)) is a typical heavy metal pollutant, making its removal from wastewater imperative. Although nanosized zero-valent iron (nZVI) and graphene-based materials are excellent remediation materials, they have drawbacks, such as agglomeration and being difficult to recycle. A facile synthesis method for decorating reduced graphene oxide (rGO) with ultrathin nZVI (within 10 nm) was explored in this study in order to develop an effective tool for Cr(VI) detoxication. Cu particles were doped in these composites for electron-transfer enhancement and were verified to improve the rate by 2.4~3.4 times. Batch experiments were conducted at different pHs, initial concentrations, ionic strengths, and humic acid (HA) concentrations. From these observations, it was found that the acid condition and appearance of Cu and rGO enhanced the treatment capacity. This procedure was fitted with a pseudo-second-order model, and the existence of NaCl and HA impeded it to some extent. Cr(VI) could be detoxified into Cr(III) and precipitated on the surface. Combining these analyses, a kinetics study, and the characterizations before and after the reaction, the removal mechanism of Cr(VI) was further discussed as a complex process involving adsorption, reduction, and precipitation. The maximum removal capacity of 156.25 mg g-1 occurred in the acid condition, providing a potential Cr(VI) remediation method.

Yielding and thixotropic cellulose microgel-based network in high-content surfactant for stably suspending of functional beads.

Functional particles, such as microcapsules of perfumes, enzymes, or anti-mite agents, are desired to stably suspend in the high-content surfactant solution, providing additional functionalities for household products. Due to the disassociation of high-content surfactant, most linear or branched polymers would fail to modify the rheological properties of the high-content surfactant solution, especially for the suspending ability. In this research, the 2,2,6,6-tetramethylpiperidine-1-oxyl oxidized bacterial cellulose microgel (T-microgel) and hydroxypropyl methylcellulose (HPMC) were employed as "island" and "chain," respectively, which could self-assemble together to fabricate a yield and thixotropic continuous network in a high-content surfactant solution. The suspending ability of microgel in high-content surfactant is better than cellulose nanofiber and carboxymethylcellulose. This is the first time to report a cellulose microgel-based rheological modifier. T-microgel/HPMC synthetic system mixed with high content surfactant presented a typical Carreau-Yasuka fluid. Meanwhile, the effects of the HPMC and surfactant on the rheological properties of the combined system were investigated, and an optimal ratio for the 'island'/'chain' synthetic system was found to modify its yield and thixotropy behavior successfully. The potential application of this combined system was explored and found to work with all kinds of surfactants at high concentrations, which is more advantageous than most commercial suspending agents.