Removal of O-Nitrophenol from Petrochemical Wastewater: Comparison Between SBR and MSBR Biological Reactors

The discharge of wastewater from various industries such as petroleum and petrochemical, pollute water resources. The presence of these pollutants in water resources will cause disorders in the ecosystem and it has various risks to human health. The effluent usually contains organic matter, including phenol and its derivatives. In this study, three different types of reactors were used in the activated sludge process to study the biological removal of o-nitrophenol from the petrochemical industrial effluent. These reactors include Continuous Moving-Bed Sequencing Batch Reactor, Moving-Bed Sequencing Batch Reactor and conventional sequencing batch reactor. For this purpose, the operational indicators of each reactor were investigated and optimized. For MSBR, active sludge volume ratio (30%), aeration flowrate (18 L/min), operation time (4h), pH (7), filler to reactor volume ratio (4.7 %) and SVI (89 ml/g) were considered. Also, For C-MSBR indicators such as initial volumetric flowrate (20 ml/min), aeration flowrate (12 L/min), filler to reactor volume ratio (5.8 %) and SVI (98 ml/g) were optimized. As SBR is structurally similar to the other reactors, only initial volumetric flowrate was considered (40 ml/min) and based on the results, this reactor has better SVI (88 ml/g) than the other two reactors. Finally, based on the optimized parameters, percentage removal of ortho nitrophenol from a synthesized effluent, analogous to Karoon Petrochemical company effluent, was investigated by C-MSBR. In addition to o-nitrophenol, other chemicals such as Toluene and Benzene were also present. The results show the indicators including ortho nitrophenol percentage removal (84.7%), Chemical Oxidation Demand (COD) (94%), Biochemical Oxidation Demand (94.8%), BOD5/COD (0.57) and SVI (74.45 ml/g) comply with environmental standards and the treated effluent can be used in irrigation and agriculture by addition of one more processing step

Dichlorido(di-2-pyridylamine)mercury(II)

In the molecule of the title compound, [HgCl2(C10H9N3)], the HgII atom is four-coordinated in a distorted tetrahedral configuration by two N atoms from the chelating di-2-pyridylamine ligand and by two Cl atoms. In the crystal structure, intermolecular N—H...Cl hydrogen bonds link the molecules into centrosymmetric dimers. There is a π–π contact between the pyridine rings [centroid–centroid distance = 3.896 (5) Å]

Hydrogen bond-mediated self-assembly of Tin (II) oxide wrapped with Chitosan/[BzPy]Cl network: An effective bionanocomposite for textile wastewater remediation

A novel and efficient bionanocomposite was synthesized by incorporating SnO into chitosan (Ch) and a room-temperature ionic liquid (RTIL). The bionanocomposite was synthesized in benzoyl pyridinium chloride [BzPy]Cl to maintain the unique properties of SnO, chitosan, and the ionic liquid. Adsorption and photodegradation processes were applied to evaluate the bionanocomposite for removing azo and anthraquinone dyes and textile wastewater. SnO/[BzPy]Cl and SnO/[BzPy]Cl/Ch samples were prepared and characterized using various techniques, including FT-IR, SEM, XRD, EDAX, XPS, DSC, TGA, nitrogen adsorption/desorption isotherm, and DRS analysis. SEM analysis revealed a hierarchical roughened rose flower-like morphology for the biocomposite. The band gap energies of SnO/[BzPy]Cl and SnO/[BzPy]Cl/chitosan were found to be 3.9 and 3.3 eV, respectively, indicating a reduction in the band gap energy with the introduction of [BzPy]Cl and chitosan. SnO/[BzPy]Cl/Ch showed high removal rates (92–95 %) for Fast Red, Blue 15, Red 120, Blue 94, Yellow 160, and Acid Orange 7 dyes. The adsorption kinetics followed a pseudo-second-order model.In addition, the effect of different photodegradation parameters such as solution pH, dye concentrations, contact time, and amount of photocatalyst, was studied. Given the optimal results obtained in removing azo and anthraquinone dyes, the SnO/[BzPy]Cl/Ch nanocomposite was used as an efficient nanocomposite for removing dyes from textile wastewater. The highest removal efficiency was found to be 95.8 %, obtained under ultraviolet and visible light. Furthermore, BOD and COD reduction analysis showed significant reductions, indicating the excellent performance of the photocatalyst

Fast chromium determination in pharmaceutical tablets by using electrochemical sensors: Preparation and comparison

In the present paper, three electrodes were prepared with the aim of detecting chromium (III) in pharmaceutical tablets and comparing their capabilities and efficiency. At first, N-(pyridine-2-ylcarbamothioyl) benzamide (NP2YCTB) was synthesized and characterized by 1H NMR, FTIR, and 13C NMR spectroscopy methods. Then, it is used as a sensing material to prepare three types of chromium potentiometry sensors including solid-state electrodes (SSE), coated wire electrodes (CWE) as asymmetric electrodes, and liquid membrane electrodes (LME) as symmetric electrodes. The responses of all electrodes were Nernstian. Field-emission scanning electron microscopy was utilized to investigate the liquid membrane morphology. The presence of chromium (III) in the membrane was proved using Energy-dispersive X-ray spectroscopy and the coordination of NP2YCTB heteroatoms with chromium (III) was confirmed by Fourier transform infrared spectroscopy. The limit of detection for SSE (3 × 10−9 mol/L) was enhanced compared with LME (7 × 10−6 mol/L) and CWE (3 × 10−7 mol/L). The response time of electrodes was very short so it was about 5–6 s for LME and CWE and 5–8 s for SSE. The sensors were used for the potentiometric determination of chromium (III) in pharmaceutical tablets and in the potentiometric titration of it with EDTA