A sensitive and selective atrazine (ATZ) electrochemical sensor was developed based on molecularly imprinted polymer (MIP). The density functional theory at B3LYP/6-31G (d, p) level and Gaussian 2009 package was used to calculate the interaction energy of template-monomers. The MIP sensing film was prepared by electropolymerization of o-phenylenediamine (o-PD) using ATZ as the template. Some factors affecting the activity of the sensor have been discussed. The performance of the sensor was characterized by cyclic voltammetry and differential pulse voltammetry.Under the optimal experimental conditions, the relative current change was linear to the concentration of ATZ in the range of 5.0×10 -9 to 1.4×10 -7 M with a detection limit of 1.0×10 -9 M. The result of selectivity experiment showed that imprint electrode has good response and selectivity towards ATZ. The proposed MIP-based sensor also showed a good stability and repeatability.

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Results in a previous study showed up to a 55% increase in saccharification rates when the initial particle size range decreased from 590 < x < 850 microm down to 33 < x < 75 microm. The smaller particle sizes also lowered the viscosity of the slurry 50-fold (for an equivalent initial solids concentration). In this study, ultrasonic irradiation was employed to further reduce the particle size of sawdust slurries below the ranges in the previous study in an attempt to further increase enzymatic saccharification rates and lower the slurry viscosity. Average particle sizes were reduced to less than 1 microm under the conditions tested. Surprisingly, the amount and rates of sugar released in this study with the approximately 1 microm particles is comparable (maximum glucose release of 30%) to, but no better than that seen for particle sizes in the range of 33 < or = x < or = 75 microm (maximum glucose release of 31%). Also surprisingly, the viscosity increased as the average particle sizes in the slurries decreased, which is opposite to the trend in the previous study. For example, there was an approximately threefold increase in the viscosity between unsonicated samples with a range of 10 < or = x < or = 75 microm and sonicated samples with a range of 0.05 < or = x < or = 12 microm. This is attributed to the variations in surface characteristics of the particles which were characterized here using X-ray diffraction profiles and SEM pictures.

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The efficient uptake of phosphate from aqueous solutions was achieved on layered double hydroxides (LDHs)-based electrodes via capacitive desalination in our previous study. The current follow-up work was mainly carried out to study the influence of various experimental parameters on the capacitive removal of phosphate using LDHs/activated carbon (LDHs/AC) composite electrodes. A series of batch experiments were implemented to investigate the experimental factors, including Mg 2+ /Al 3+ ratios (2, 3, and 4), trivalent metal cations (Al 3+ , Fe 3+ , Cr 3+), initial solution pH (from 3 to 10), coexisting anions (NO 3-, Cl-, SO 4 2-), and ion strengths, in capacitive deionization. The electrode materials before and after capacitive deionization were characterized to reinforce the analysis of the adsorption mechanisms by X-ray powder diffraction, scanning electron microscopy, energy dispersive X-ray, cyclic voltammetry, and electrochemical impedance spectroscopy. Results indicated that the Mg-Al LDHs/AC electrodes exhibited higher phosphate adsorption capacity (80.43 mg PO 4 3-/g), more regular morphology, and higher degree of crystallinity than that of Mg-Fe LDHs/AC and Mg-Cr LDHs/AC. Increasing Mg 2+ /Al 3+ ratios enhanced the adsorption capacity of phosphate. The uptake of phosphate by Mg-Al LDHs/AC under circumneutral pH and low ion strength reached the maximum level. Furthermore, the presence of coexisting anions lowered the adsorption capacity of phosphate mainly due to the occurrence of a compressed electrical double layer. Therefore, the influence of different experimental parameters on phosphate removal via capacitive deionization by Mg-Al LDHs/AC necessitates a 3 systematic investigation to optimize the preparation conditions of LDHs-based electrodes and several important operating parameters.