The current study aimed to investigate the effect of counterions on hydrothermally synthesized hydrozincite (zinc hydroxide carbonate), which was thermally converted to generate ZnO nanostructures, which are an efficient nanoadsorbent for the removal of Reactive Black 5 (RB5) dye from wastewater. Hydrozincite nanospheres and flower-like structures were hydrothermally prepared using various zinc salts (sulfate, acetate, and nitrate) and ammonium carbonate in a molar ratio of 1 : 3, respectively, at 120 C for 3 h. The morphology and crystallite size of the hydrozincite precursor were effectively controlled via the parameters of the hydrothermal reaction. Interestingly, sulfate was the optimum counterion, as zinc sulfate salt produced pure hydrozincite nanospheres with the smallest crystallite size ($13.57 nm), which were consequently thermally decomposed at 400 C for 1 h to produce pure nanosized ZnO ($10 nm). The compositions of the as-synthesized products were determined by means of FT-IR, FE-SEM, HR-TEM, XRD, zeta potential, BET, and thermal analyses. An adsorption study showed a much higher adsorption capacity (80.9 mg g À1 ) of the as-prepared ZnO nanoparticles toward RB5 dye. The adsorption of RB5 dye followed pseudo-second-order kinetics. In addition, the equilibrium adsorption of RB5 dye was best described by a Langmuir isotherm model and the calculated thermodynamic parameters, DG 0 (from À4.027 to À7.533 kJ mol À1 ), DH 0 (30.798 kJ mol À1 ), and E a (29.105 kJ mol À1 ), indicate the spontaneous, endothermic, and physisorptive nature of the adsorption process.

No abstract

A spectrophotometric procedure for the determination of sertraline hydrochloride (Sert) and/or clidinium bromide (Clid) in bulk sample and in dosage forms was developed. The purpose of this work was to develop a rapid, simple, inexpensive, precise, and accurate visible spectrophotometric method. The procedure is based on formation of an ion-pair complex by their reaction with bromocresol green (BCG), bromophenol blue (BPB), and bromothymol blue (BTB) in buffered aqueous solution at pH 3. The colored products are extracted into a polar solvent and measured spectrophotometrically at the optimum λmax for each complex. Optimization of different experimental conditions is described. Regression analysis of Beer-Lambert plots showed good correlation in the concentration range of 1–30 µg mL−1. The apparent molar absorptivity, Sandell sensitivity, detection and quantification limits were calculated. For more accurate analysis, Ringbom optimum concentration range of 2–27 µg mL−1 was used. The developed methods were successfully applied for the determination of sertraline hydrochloride and clidinium bromide in bulk in pharmaceutical formulations without any interference from common excipients. The procedure has the advantage of being highly sensitive and simple for the determination of the studied drugs, weak UV-absorbing compounds.

The electronic absorption spectra of some hydroxamic acid oxime derivatives and Schiff's base derivatives in polar (ethanol) and nonpolar (CCl4) solvents, as well as in some other organic solvents of different polarities, were investigated; the variation of absorbance with pH was utilized for the determination of pKa, and Δ G* values. The important bands in the IR spectra as well as the main signals of the NMR spectra are also discussed in relation to the molecular structure.

The herbicide butralin (Amex) was injected at the recommended rate ( 2.5 Kg/fed) through subsurface and surface drip irrigation systems with two flow rates of 8 and12 lph/m under sandy soil conditions of the newly reclaimed areas of Egypt.Maximum cucumber yield of 8360 kg/fed. was achieved using subsurface drip irrigation systems at 8 lph/m flow rate and 50 cm emitters spacing, in manure sandy soil Water use efficiency (WUE) ranged from 4.042 to 3.955 kg/m 3 with 8 and 12 lph/m flow rates, respectively for subsurface irrigation systems 50 and 33 cm emitters spacing in manured sandy soil. The application of herbicide butralin (Amex) with subsurface drip irrigation systems, 50 cm emitters spacing proved more suitable to increase cucumber yield, and to achieve more uniformity in water distribution (8 lph/m) for irrigation systems. No butralin (Amex) residues were detected in cucumber yield produced under subsurface drip irrigation systems at 10 cm depth for the 50 cm emitters spacing and 8 lph/m flow rate.