Optimization of operational parameters by Taguchi design for imidacloprid oxidation by microwave‐activated persulfate

2018 ◽  
Vol 37 (5) ◽  
pp. 1632-1637 ◽  
Author(s):  
Nevim Genç ◽  
Elif Durna
Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2532 ◽  
Author(s):  
Md. Nahid Pervez ◽  
Felix Y. Telegin ◽  
Yingjie Cai ◽  
Dongsheng Xia ◽  
Tiziano Zarra ◽  
...  

In this study, a Fenton-activated persulfate (Fe2+/PS) system was introduced for the efficient degradation of Mordant Blue 9 (MB 9) as a textile dye in an aqueous solution. Results showed that the degradation of MB 9 was markedly influenced by operational parameters, such as initial pH, PS concentration, Fe2+ concentration, and initial dye concentration. Optimal reaction conditions were then determined. Inorganic anions, such as Cl− and HCO3−, enhanced the degradation efficiency of MB 9 under optimal conditions. Addition of HCO3− reduced the degradation performance of MB 9, whereas the addition of Cl− increased the degradation percentage of MB 9. In addition, quenching experiments were conducted using methanol and tert-butyl alcohol as scavengers, and methanol was identified as an effective scavenger. Thus, the degradation of MB 9 was attributed to S O 4 • − and •OH radicals. The degradation and mineralization efficiency of MB 9 was significantly reduced using the conventional Fenton process i.e., Fe2+/ hydrogen peroxide (HP) because of the formation of a Fe complex during degradation. Meanwhile, the Fe2+/persulfate (PS) system improved the degradation and mineralization performance.


Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 733 ◽  
Author(s):  
Md. Nahid Pervez ◽  
Wei He ◽  
Tiziano Zarra ◽  
Vincenzo Naddeo ◽  
Yaping Zhao

Persulfate (PS)-activated, iron-based heterogeneous catalysts have attracted significant attention as a potential advanced and sustainable water purification system. Herein, a novel Fe3O4 impregnated graphene oxide (Fe3O4@GO)-activated persulfate system (Fe3O4@GO+K2S2O8) was synthesized by following a sustainable protocol and was tested on real wastewater containing dye pollutants. In the presence of the PS-activated system, the degradation efficiency of Rhodamine B (RhB) was significantly increased to a level of ≈95% compared with that of Fe3O4 (≈25%). The influences of different operational parameters, including solution pH, persulfate dosage, and RhB concentration, were systemically evaluated. This system maintained its catalytic activity and durability with a negligible amount of iron leached during successive recirculation experiments. The degradation intermediates were further identified through reactive oxygen species (ROS) studies, where surface-bound SO4− was found to be dominant radical for RhB degradation. Moreover, the degradation mechanism of RhB in the Fe3O4@GO+K2S2O8 system was discussed. Finally, the results indicate that the persulfate-activated Fe3O4@GO catalyst provided an effective pathway for the degradation of dye pollutants in real wastewater treatment.


2017 ◽  
Vol 19 (2) ◽  
pp. 72-77 ◽  
Author(s):  
Sahand Jorfi ◽  
Sudabeh Pourfadakari ◽  
Mehdi Ahmadi ◽  
Hamideh Akbari

Abstract Thermally activated persulfate efficiency for the treatment of a recalcitrant high TDS wastewater was investigated. The specific character of studied wastewater was high TDS content of around 23820 mg/L and BOD5/COD ratio of 0.07. Effective operational parameters including initial pH values of 3–9, reaction temperature of 40–80°C and persulfate concentrations of 0.5–5 g/L for COD removal were investigated in batch mode experiments. Removal efficiency was pH and temperature dependent. The COD and TOC removal of 94.3% and 82.8% were obtained at persulfate concentration of 4 g/L, initial pH value of 5 and temperature of 70°C after 180 min for initial COD concentration of 1410 mg/L. The pseudo first-order kinetic model was best fitted with COD removal (R2 = 0.94).


Author(s):  
David C Joy

The electron source is the most important component of the Scanning electron microscope (SEM) since it is this which will determine the overall performance of the machine. The gun performance can be described in terms of quantities such as its brightness, its source size, its energy spread, and its stability and, depending on the chosen application, any of these factors may be the most significant one. The task of the electron gun in an SEM is, in fact, particularly difficult because of the very wide range of operational parameters that may be required e.g a variation in probe size of from a few angstroms to a few microns, and a probe current which may go from less than a pico-amp to more than a microamp. This wide range of operating parameters makes the choice of the optimum source for scanning microscopy a difficult decision.Historically, the first step up from the sealed glass tube ‘cathode ray generator’ was the simple, diode, tungsten thermionic emitter.


2010 ◽  
Vol 9 (10) ◽  
pp. 1451-1457 ◽  
Author(s):  
Corina-Petronela Musteret ◽  
Daniela Cailean ◽  
George Barjoveanu ◽  
Carmen Teodosiu

Author(s):  
А. Yu. Izmaylov ◽  
Ya. P. Lobachevskiy ◽  
V. К. Khoroshenkov ◽  
N. Т. Goncharov ◽  
S. E. Lonin ◽  
...  

The introduction of information and digital technologies that support and support all technological processes in the field is an urgent need for the development and implementation of such technology. An organisationally complex and financially intensive project is necessary because of the wide variety of economic entities that differ in the size of production, forms of ownership and socio-economic conditions of production. Automated information control system for mobile units agricultural enterprise provides those-Niko-economic performance, optimum capacity utilization through the use of timely and reliable information on technology. Machine and tractor aggregates are appertained as control objects with variable structure, which is explained by possibility of the system formation from tractor or field machines mobile units with various purposes: tillable, cultivatable, sowing, harvesting and etc. This MTA feature was determined creation of digital control systems of two groups of automatic control and management of the basic energy and operational parameters: tractors, machines and vehicles as part of MTA. To the first group are appertained the automatic control system of tractor motor component loading, motion speed, frictional sliding. To the second group – automatic regulation system of operating depth, seed rate, treatment of liquid combined fertilizers and crop protection agents, filling and driving of various MTA. Novelty of researches consists in methodology of the organization of the centralized control and management of various technological processes at carrying out field works.


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