Selective Chelating Resin for Copper Removal and Recovery in Aqueous Acidic Solution Generated from Synthetic Copper-Citrate Complexes from Bioleaching of E-waste

This research focused on batch experiment using a new generation of chelating resins via an ion exchange process to describe the metabolic adsorption and desorption capacity onto iminodiacetic acid/Chelex 100, bis-pyridylmethyl amine/Dowex m4195, and aminomethyl phosphonic/Lewatit TP260 functional groups in bioleaching. The results showed that Dowex m4195 had the highest performance of adsorption capacity for copper removal in both H+-form and Na+-form. Results for Lewatit TP260 and Chelex 100 revealed lower adsorption performance than results for Dowex m4195. The investigation of desorption from chelating resins was carried out, and it was found that 2 M ammonium hydroxide concentration provided the best desorption capacity of about 64.86% for the H+-form Dowex m4195 followed by 52.55% with 2 M sulfuric acid. Lewatit with 2 M hydrochloric acid gave the best desorption performance in Na+-form while Chelex 100 using hydrochloric at 1 M and 2 M provided similar results in terms of the H+-form and Na+-form. As aspects of the selective chelating resins for copper (II) ions in aqueous acidic solution generated from synthetic copper-citrate complexes from bioleaching of e-waste were considered, H+-form Dowex m4195 was a good performer in adsorption using ammonium hydroxide for the desorption. However, chelating resins used were subsequently reused for more than five cycles with an acidic and basic solution. It can be concluded from these results that selective chelating resins could be used as an alternative for the treatment of copper (II) ions contained in e-waste or application to other divalent metals in wastewater for sustainable water and adsorbent reuse as circular economy.

Investigation of ZnO doping on LaFeO3/Fe2O3 prepared from yarosite mineral extraction for ethanol gas sensor applications

<abstract> <p>In this study, we used a natural resource, yarosite minerals, as a Fe₂O₃ precursor. Yarosite minerals were used for the synthesis of LaFeO₃/Fe₂O₃ doped with ZnO via a co-precipitation method using ammonium hydroxide, which produced a light brown powder. Then, an ethanol gas sensor was prepared using a screen-printing technique and characterized using gas chamber tools at 100,200, and 300 ppm of ethanol gas to investigate the sensor's performance. Several factors that substantiate electrical properties such as crystal and morphological structures were also studied using X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM), respectively. The crystallite size decreased from about 61.4 nm to 28.8 nm after 0.5 mol% ZnO was added. The SEM characterization images informed that the modified LaFeO₃ was relatively the same but not uniform. Lastly, the sensor's electrical properties exhibited a high response of about 257% to 309% at an operating temperature that decreased from 205 ℃ to 180 ℃. This finding showed that these natural resources have the potential to be applied in the development of ethanol gas sensors in the future. Hence, yarosite minerals can be considered a good natural resource that can be further explored to produce an ethanol gas sensor with more sensitive response. In addition, this method reduces the cost of material purchase.</p> </abstract>

In situ mineralized PLGA/zwitterionic hydrogel composite scaffolds enable high-efficiency rhBMP‑2 release for critical-sized bone healing

Seeking an osteoconductive and osteoinductive scaffold is highly desirable for functional restoration of large bone defects. Here, we report an in situ mineralized poly(lactic-co-glycolic acid)/poly[2-(methacryloyloxy)ethyl] dimethyl-(3-sulfopropyl)ammonium hydroxide hydrogel (PLGA/PSBMA) scaffolds...

Preparation and characterization of CdS thin film using chemical bath deposition (CBD) technique for solar cell application

The structural properties of CBD deposited CdS thin films have been studied by varying the processing parameters and Cd/S ratio of the starting Precursors in order to better understand the growth conditions. A CdS thin film was prepared on glass substrate by CBD method from a bath containing Thiourea and Ammonium hydroxide. The structural analysis was performed by X-ray Diffraction (XRD). The deposited CdS thin film was a cubic phase with small nano crystalline grains. The film was deposited at 60°C for 2 hours. After sintering the film at 300°C for 1 hour the color of the film was changed like dark yellowish and the thickness of the film was obtained 100 nm. The FTIR was done at room temperature over 350 cm-1 to 4500 cm-1 and it showed the existence of different functional group in the sample and their probable source. These studies have allowed us to establish a standard set of conditions for the fabrication of homogeneous and continuous very thin CdS films in laboratory and this preparation technique is also suitable for preparing highly efficient thin film due to its advantages such as simple, large area films, low deposition temperature and low-cost method.

Synthesis of Hematite Nano Material and Its Effect on Properties of Water Based Drilling Mud

The worldwide use of nanotechnology in most industries, such as in oil and gas industries, the world now has been directed towards introducing this modern technology in drilling fluids for the purpose of reaching and extracting hydrocarbons that exist at high depth where high temperatures and high pressure present using this technology to achieve the required mud properties with lowest cost. In this research, the particles of Nano hematite were prepared in laboratory using two methods, the first method by chemical reaction between iron nitrate (Fe (NO3)3• 9H2O) and ammonium hydroxide (NH4OH), after that, prepared Nano-materials were subjected to AFM, XRD testing in order to investigate the size and type of particles, the investigations showed that the formed particles were Fe2O3 (<100nm). The second method is similar to the first method except adding (CTAB) material in order to reduce the interfacial tension leading to 4.5nm Nano-material. Three samples of drilling mud were prepared, the first sample was prepared from water and bentonite only, the second sample was prepared from water, bentonite and nano (prepared from first method), the third samples was prepared from water, bentonite and nano (prepared from second method), rheological properties, filtration, density, lubricity, sagging and magnetism properties were measured by analyzing and comparing the results. The results were obtained showed that the small effect of nano material filtration, density, lubricity, and sagging properties, except the viscosity increase when the second sample of Nano hematite was added to the mud prepared from water and bentonite. Also, the magnetism increase when the second sample of nano hematite was added to the mud prepared from water and bentonite, due to the difference in the molecular arrangement caused by the presence of CTAB.

Boosted Ultraviolet Photodetection of AlGaN Quantum-Disk Nanowires via Rational Surface Passivation

Self-assembled AlGaN nanowires (NWs) are regarded as promising structures in the pursuit of ultraviolet photodetectors (UV PDs). However, AlGaN nanowire-based PDs currently suffer from degraded performance partially owing to the existence of outstanding surface-related defects/traps as a result of its large surface-to-volume-ratio feature. Here, we propose an effective passivation approach to suppress such surface states via tetramethyl ammonium hydroxide (TMAH) solution treatment. We successfully demonstrate a fabrication of UV PDs using TMAH-passivated AlGaN quantum-disk NWs and investigate their optical and electrical properties. Particularly, the dark current can be significantly reduced by an order of magnitude after surface passivation, thus leading to the improvement of photoresponsivity and detectivity. The underlying mechanism for such boost can be ascribed to the effective elimination of oxygen-related surface states on the nanowire surface. Consequently, an AlGaN nanowire UV PD with a low dark current of 6.22×10-9 A, a large responsivity of 0.95 A W-1, and a high detectivity of 6.4×1011 Jones has been achieved.

High-yield production of secoisolariciresinol diglucoside from flaxseed hull by extraction with alcoholic ammonium hydroxide and chromatography on microporous resin

This study used alcoholic ammonium hydroxide to directly hydrolyze and extract secoisolariciresinol diglucoside (SDG) from flaxseed hull in a one pot reaction. The optimal extraction conditions, including the concentration of ammonium hydroxide, extraction time, and temperature, were examined in single factor experiments, followed by response surface methodology (RSM) with 3-level, 3-factor Box-Behnken experiments. As a result, the optimal extraction conditions were determined as follows: material-liquid ratio 1:20, percentage of reagent ammonium hydroxide (25–28% of NH3 in water) in ethanol 33.7% (pH = 12.9), extraction time 4.9 h, and extraction temperature 75.3 °C. Under these conditions, the yield of SDG, as measured by ultra-high-performance liquid chromatography-mass spectrometry, was 23.3 mg/g, consistent with the predicted content of SDG in flaxseed hull (23.0 mg/g). Further, 30.0 g of pulverized flaxseed hull was extracted under the optimal conditions, and the extract was subjected to a single run of macroporous resin chromatography to obtain 772.1 mg of a fraction with an SDG content exceeding 76.1%. Subsequent chromatography on Sephadex LH20, yielded 602.8 mg SDG of 98.0% purity, and the yield was 20.1 mg/g (2.0%) from flaxseed hulls. Thus, one-pot hydrolysis and extraction of SDG using alcoholic ammonium hydroxide is simple, and of high-yield. Graphical abstract

Results of compact facility work with anaerobic treatment of highly concentrated runoffs

This scientific work is devoted to the results of the local treatment facilities’ work for food enterprises sewerage. The complex under consideration is intended for the anaerobic processing of whey, formed during fermented milk production. Whey is one of the specific organic substances, which main component is lactose (sucrose). It is converted under anaerobic conditions into lactic acid, which is a metabolic dead end. The capacity can be used as a homogenizing tank, obtained in this way. In the future, it is proposed to increase the homogenizer volume to 100 m3. It is recommended to use ammonium hydroxide or sulfate to ensure the required ratio between COD and biogenic element (nitrogen) in the loaded whey. Possible biogenic additives can be sewage sludge or slurry. The experience of adjustment was shown that slurry from cattle farms was quite simple, inexpensive and quite effective. Slurry can be injected in 3-4 m3 every 2-3 days. The stability of pH values in the bioreactor can be ensured by the correct placement of sensors for monitoring this indicator and by changing the method of alkali introduction. It is recommended to install pH control sensors at the bottom of the bioreactor, instead of whey loading pipeline. In order to provide for fractional injection of alkali, we should introduce part of the alkali at the homogenization stage, and part directly into the bioreactor. For an unimpeded build-up of anaerobic biomass, it is recommended to replace the centrifuge thickener operating with flocculant with the classic version of thickening in a compactor without flocculant adding.