Treatment of phenol formaldehyde production wastewater by electrooxidation-electrofenton successive processes

ABSTRACT

Treatments of phenol formaldehyde producing wastewater (PFPW) by electrooxidation (EO) and electro-Fenton (EF) successive processes were carried out in a batch electrolytic reactor using graphite (Gr) and stainless steel (Ss) electrodes. After the completion of the EO process, the wastewater was further treated with EF process. The influence of operating variables such as current density, operating time, initial pH_i and H₂O₂ concentration was evaluated for removals of phenol, TOC and COD in PFPW. Gr/Gr, Gr/Ss or Ss/Ss and Ss/Gr electrode pair were used as anode and cathode. The best removal efficiency in the EO process was obtained with Gr/Gr (93%) as compared to Gr/Ss (82%), Ss/Ss (63%) and Ss/Gr (55%). The removal efficiencies for the EO process using Gr-Gr electrode pair were obtained as 93% for phenol, 61% for COD and 44% for TOC at initial pH_i 7,5 g/L of NaCl, 50 mA/cm² and 5 h. In the EF process, the removal efficiencies at pH_i 3,5 mA/cm² and 30 mM H₂O₂ and 45 min were 100% for phenol, 76% for COD and 59% for TOC. This study provided that the successive processes are an effective method for the removal of phenolic compounds from the wastewater.     

Classification using proximity catch digraphs

Machine Learning - We employ random geometric digraphs to construct semi-parametric classifiers. These data-random digraphs belong to parameterized random digraph families called proximity catch...     

Effects of Mn and Gd Co-substituted into ZnO on Structural and Magnetic Properties

We have worked on the structural and magnetic properties of Zn_0.99?xMn_0.01Gd _x O _δ (for x = 0.02, 0.03, and 0.04) compounds prepared by using a sol–gel method. The x-ray diffraction, scanning electron microscopy, and energy dispersive x-ray spectroscopy were used to understand the structural properties of the samples. We observed that co-substitution of Mn (1 %) and Gd (2–4 %) into the ZnO does not change the hexagonal structure. Scanning electron microscope (SEM) images show us that the grain size decreases with the increasing amount of the Gd into the ZnO matrix. The magnetic properties of the samples have been investigated by using magnetic hysteresis and DC susceptibility measurements. The ZMG1 sample shows a weak ferromagnetic behavior at room temperature, whereas the ZMG2 and ZMG3 samples exhibit a paramagnetic nature. Furthermore, it is also found that the magnetizations of the samples decrease with increasing Gd content in the ZnMnO system due to the enhancing interaction between Gd ³⁺ ions. We summarize that the co-substitution of Mn and Gd into the ZnO generates a room-temperature ferromagnetism, but it still needs more work to obtain strong and high coercivity magnetic loops for applications.     

Efficiency of Gold Nano Particles on the Autoxidized Soybean Oil Polymer: Fractionation and Structural Analysis

Polyunsaturated plant oils have gained great interest as monomers to produce biodegradable polymers obtained from renewable resources due to the limited existing sources of petroleum oil and environmental issues. Soybean oil was autoxidized by exposure to atomospheric oxygen at room temperature with or without the presence of gold nanoparticles (Au NPs) 5–41 days. When the autoxidation process was catalyzed with Au NPs, the molecular weight of the oxidized oil was increased in 5 days. In contrast to this, without Au NPs, the oxidized oil was still a fluidized liquid. Autoxidized soybean oil polymer in toluene solution with gold NP showed a surface plasmon resonance at λ_max = 540 nm in a UV–VIS spectrometer and a fluorescence emission spectrum at λ_max = 450 nm, when it was irradiated at λ_max = 390 nm. The higher molecular weight of the polymeric oils was successively fractionated by the extraction from the solvent‐non‐solvent mixture CHCl₃/petroleum ether with the volume ratio of 5:15. Three polymeric oils fractions with different molecular weight (ca 1000, 4000, and 40,000 g/mol) were obtained. GC–MS analysis, ¹H‐NMR and GPC techniques were used in the structural analysis of the fractionated polymeric oils.     

Multi-machine earliness and tardiness scheduling problem: an interconnected neural network approach

This paper addresses the problem of scheduling a set of independent jobs with sequence-dependent setups and distinct due dates on non-uniform multi-machines to minimize the total weighted earliness and tardiness, and explores the use of artificial neural networks as a valid alternative to the traditional scheduling approaches. The objective is to propose a dynamical gradient neural network, which employs a penalty function approach with time varying coefficients for the solution of the problem which is known to be NP-hard. After the appropriate energy function was constructed, the dynamics are defined by steepest gradient descent on the energy function. The proposed neural network system is composed of two maximum neural networks, three piecewise linear and one log-sigmoid network all of which interact with each other. The motivation for using maximum networks is to reduce the network complexity and to obtain a simplified energy function. To overcome the tradeoff problem encountered in using the penalty function approach, a time varying penalty coefficient methodology is proposed to be used during simulation experiments. Simulation results of the proposed approach on a scheduling problem indicate that the proposed coupled network yields an optimal solution which makes it attractive for applications of larger sized problems.     

A Survey of Handover Techniques for Wireless ATM Networks

This paper provides a review and comprehensivecomparison of existing handover schemes proposed forwireless ATM networks. Existing schemes include thoseproposed by NEC, Olivetti, Bell Labs, Cambridge, Stanford, CMU, Berkeley, Michigan, VTT, andColumbia. We highlight the methodologies employed by thevarious schemes and reveal their differences. We discussissues related to the effect of ATM switch architectures on mobility implementation and on futurehandover paradigms.     

Dipole moments of styrene/4-vinylpyridine copolymers—II: Relation to microstructure

Mean-square dipole moment values of styrene/4-vinylpyridine (S4VP) copolymers determined at 25–60°C in 1,4-dioxane solutions were related to the microstructure of the chains. Data on the synthesis and dipole moments of S4VP copolymers were used to calculate the distribution of triad fractions and effective dipole moments of styrene, S-centred, and 4-vinylpyridine, V-centred, fractions in the copolymer chains. The relative magnitudes of the effective dipole moment values calculated for each type of triad reflect the effect of dipole–dipole interactions on these values.     

How accurately do drivers evaluate their own driving behavior? An on-road observational study

Self-assessment of driving skills became a noteworthy research subject in traffic psychology, since by knowing one's strenghts and weaknesses, drivers can take an efficient compensatory action to moderate risk and to ensure safety in hazardous environments. The current study aims to investigate drivers’ self-conception of their own driving skills and behavior in relation to expert evaluations of their actual driving, by using naturalistic and systematic observation method during actual on-road driving session and to assess the different aspects of driving via comprehensive scales sensitive to different specific aspects of driving. 19–63 years old male participants (N = 158) attended an on-road driving session lasting approximately 80 min (45 km). During the driving session, drivers’ errors and violations were recorded by an expert observer. At the end of the driving session, observers completed the driver evaluation questionnaire, while drivers completed the driving self-evaluation questionnaire and Driver Behavior Questionnaire (DBQ). Low to moderate correlations between driver and observer evaluations of driving skills and behavior, mainly on errors and violations of speed and traffic lights was found. Furthermore, the robust finding that drivers evaluate their driving performance as better than the expert was replicated. Over-positive appraisal was higher among drivers with higher error/violation score and with the ones that were evaluated by the expert as “unsafe”. We suggest that the traffic environment might be regulated by increasing feedback indicators of errors and violations, which in turn might increase the insight into driving performance. Improving self-awareness by training and feedback sessions might play a key role for reducing the probability of risk in their driving activity.     

Neuroendocrine cell hyperplasia in colonic tissue used for long term augmentation cystoplasty

A case of torsion of the wandering spleen with splenic infarction is reported. The medical imaging studies performed with typical findings are described. Case reports have been reviewed. Although rare, torsion of the spleen remains an important differential diagnosis in patients presenting with acute abdominal pain. Early intervention is necessary to reduce the risk of splenic infarction and other complications, and an increased awareness of the condition together with the use of appropriate medical imaging can lead to the correct diagnosis more readily.     

Photoinitiated synthesis of poly(poly(ethylene glycol) methacrylate-co-diethyl amino ethyl methacrylate) superabsorbent hydrogels for dye adsorption

Random copolymers of poly(ethylene glycol) methacrylate (PEGM), and diethyl amino ethyl methacrylate (DEAEM) were synthesized at low, and high conversions by photoinitiation. Crosslinked poly(PEGM-co-DEAEM) samples were obtained, and characterized by FTIR, SEM, DSC, TGA, and elemental analyses. Swelling behavior of the copolymers revealed that the copolymers acted as superabsorbent hydrogels. The monomer reactivity ratios were calculated using Fineman Ross, Extended Kelen Tüdøs , and Mayo Lewis methods that gave r₁(PEGM) = 0.90, r₂(DEAEM) = 0.14 at low conversions. At high conversions r₁ and r₂ values were calculated as 1.01 and 0.40, respectively. Adsorption isotherms of methyl orange (MO) onto hydrogels were studied using Langmuir, Freundlich, and Temkin models. The experimental data fitted well with the Langmuir equation. The maximum adsorption capacity for MO was 212.7 mg g⁻¹ at pH = 3. The adsorption data gave best fit with the pseudo-second order kinetic model. Thermodynamic evaluation showed spontaneous nature for MO adsorption onto poly(PEGM-co-DEAEM) hydrogels. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47707.