REMOVAL OF HG(II) METAL IONS USING KAOLIN ADSORBENTS MODIFIED WITH ANIONIC SURFACTANT AND EFFICIENT ULTRASONIC ASSISTED

This study reported the reduction of metal Hg(II) from water using natural kaolinite (NK) based adsorbents compared with modified kaolinite adsorbents with Hexadecyl trimethyl ammonium bromide anionic surfactants using ultrasonic technology (SMK). These adsorbent samples were characterized using several different techniques such as FTIR, X-RD and AAS analysis. The adsorption capacity is influenced by variables such as the contact time and adsorben dosage. The results of the analysis reported that the maximum waste reduction efficiency occurs in modified kaolin (SMK), where adsorption occurs faster than natural kaolin (NK). The maximum persentation is 94.57% for metal removal efficiency using modified kaolin at the contact time of 45 minutes and the dose of adsobene 1.4 g, while kaolin without modification is 73.83% of efficiency at the contact time of 60 minutes the adsobent dose was 1.4 g. The use of the adsorption method with the help of ultrasonic technology is proven to be more efficient in accelerating the removal of Hg2+ ions by increasing the surface dispersion of the adsorbent with metal ions in water. The adsorption kinetics model that is suitable for calculating the adsorption capacity of the adsorbent in the removal of Hg2+ ions using unmodified kaolin is pseudo-second-order models.

Magical Mathematical Formulas for Nanoboxes

Hollow nanostructures are at the forefront of many scientific endeavors. These consist of nanoboxes, nanocages, nanoframes, and nanotubes. We examine the mathematics of atomic coordination in nanoboxes. Such structures consist of a hollow box with n shells and t outer layers. The magical formulas we derive depend on both n and t. We find that nanoboxes with t = 2 or 3, or walls with only a few layers generally have bulk coordinated atoms. The benefits of low-coordination in nanostructures is shown to only occur when the wall thickness is much thinner than normally synthesized. The case where t = 1 is unique, and has distinct magic formulas. Such low-coordinated nanoboxes are of interest for a myriad variety of applications, including batteries, fuel cells, plasmonic, catalytic and biomedical uses. Given these formulas, it is possible to determine the surface dispersion of the nanoboxes. We expect these formulas to be useful in understanding how the atomic coordination varies with n and t within a nanobox.

Double-Nozzle Flame Spray Pyrolysis as a Potent Technology to Engineer Noble Metal-TiO2 Nanophotocatalysts for Efficient H2 Production

Noble metal-TiO2 nanohybrids, NM0-TiO2, (NM0 = Pt0, Pd0, Au0, Ag0) have been engineered by One-Nozzle Flame Spray Pyrolysis (ON-FSP) and Double-Nozzle Flame Spray Pyrolysis (DN-FSP), by controlling the method of noble metal deposition to the TiO2 matrix. A comparative screening of the two FSP methods was realized, using the NM0-TiO2 photocatalysts for H2 production from H2O/methanol. The results show that the DN-FSP process allows engineering of more efficient NM0-TiO2 nanophotocatalysts. This is attributed to the better surface-dispersion and narrower size-distribution of the noble metal onto the TiO2 matrix. In addition, DN-FSP process promoted the formation of intraband states in NM0-TiO2, lowering the band-gap of the nanophotocatalysts. Thus, the present study demonstrates that DN-FSP process is a highly efficient technology for fine engineering of photocatalysts, which adds up to the inherent scalability of Flame Spray Pyrolysis towards industrial-scale production of nanophotocatalysts.

Small-Scale Dispersion in the Presence of Langmuir Circulation

We present an analysis of ocean surface dispersion characteristics, on 1–100-m scales, obtained by optically tracking a release of bamboo plates for 2 h in the northern Gulf of Mexico. Under sustained 5–6 m s−1 winds, energetic Langmuir cells are clearly delineated in the spatially dense plate observations. Within 10 min of release, the plates collect in windrows with 15-m spacing aligned with the wind. Windrow spacing grows, through windrow merger, to 40 m after 20 min and then expands at a slower rate to 50 m. The presence of Langmuir cells produces strong horizontal anisotropy and scale dependence in all surface dispersion statistics computed from the plate observations. Relative dispersion in the crosswind direction initially dominates but eventually saturates, while downwind dispersion exhibits continual growth consistent with contributions from both turbulent fluctuations and organized mean shear. Longitudinal velocity differences in the crosswind direction indicate mean convergence at scales below the Langmuir cell diameter and mean divergence at larger scales. Although the second-order structure function measured by contemporaneous GPS-tracked surface drifters drogued at ~0.5 m shows persistent r2/3 power law scaling down to 100–200-m separation scales, the second-order structure function for the very near surface plates observations has considerably higher energy and significantly shallower slope at scales below 100 m. This is consistent with contemporaneous data from undrogued surface drifters and previously published model results indicating shallowing spectra in the presence of direct wind-wave forcing mechanisms.

Ultrasonic control of the level of the heterogeneous surface medium in mining

Topical One of the major problems of controlling the level of ore or moving fluid (slurry) is recording the reflected signal. Due to evident heterogeneity of the reflecting surface, dispersion of an ultrasonic wave greatly attenuates the reflected signal making it difficult to detect it against random noises. In this case, the only way to solve this problem is application of acoustic reflectors. To analyze this issue, a scheme of the conventional reflector with a radiator-receiver is under study. Efficiency of the acoustic reflector in recording the reflected signal is evaluated. The design of developed recording devices for ultrasonic control over fluid and solid media with heterogeneous surfaces allows increasing their accuracy and reliability due to receiving and transmitting a low-level signal in industrial noises. Industrial testing indicates that the developed ultrasonic device controlling lumpiness of ore materials produces a measuring error of under 1.5%, while efficiency of technological aggregates produced by the ultrasonic method based on measuring the level of the slurry in technological chutes of concentration plants can be evaluated with the ±1% error.