Scaling-up of microbial electrosynthesis with multiple electrodes for in situ production of hydrogen peroxide.

Microbial electrosynthesis system (MES) has recently been shown to be a promising alternative way for realizing in situ and energy-saving synthesis of hydrogen peroxide (H2O2). Although promising, the scaling-up feasibility of such a process is rarely reported. In this study, a 20-L up-scaled two-chamber MES reactor was developed and investigated for in situ and efficient H2O2 electrosynthesis. Maximum H2O2 production rate of 10.82 mg L-1 h-1 and cumulative H2O2 concentration of 454.44 mg L-1 within 42 h were obtained with an input voltage of 0.6 V, cathodic aeration velocity of 0.045 mL min-1 mL-1, 50 mM Na2SO4, and initial pH 3. The electrical energy consumption regarding direct input voltage was only 0.239 kWh kg-1 H2O2, which was further much lower compared with laboratory-scale systems. The obtained results suggested that the future industrialization of MES technology for in situ synthesis of H2O2 and further application in environmental remediation have broad prospects.

Towards smart biomanufacturing: a perspective on recent developments in industrial measurement and monitoring technologies for bio-based production processes.

The biomanufacturing industry has now the opportunity to upgrade its production processes to be in harmony with the latest industrial revolution. Technology creates capabilities that enable smart manufacturing while still complying with unfolding regulations. However, many biomanufacturing companies, especially in the biopharma sector, still have a long way to go to fully benefit from smart manufacturing as they first need to transition their current operations to an information-driven future. One of the most significant obstacles towards the implementation of smart biomanufacturing is the collection of large sets of relevant data. Therefore, in this work, we both summarize the advances that have been made to date with regards to the monitoring and control of bioprocesses, and highlight some of the key technologies that have the potential to contribute to gathering big data. Empowering the current biomanufacturing industry to transition to Industry 4.0 operations allows for improved productivity through information-driven automation, not only by developing infrastructure, but also by introducing more advanced monitoring and control strategies.

Removal of Phenazopyridine from wastewater by merging biological and electrochemical methods via Azolla filiculoides and electro-Fenton process.

In the present study, the potential of Azolla filiculoides (A. filiculoides) was first investigated for degradation of Phenazopyridine (PhP), an analgesic drug. The effects of main variables such as initial pharmaceutical concentration, amount of plant, and pH were studied on the efficiency of the biological process. It was observed that A. filiculoides was able to remove pharmaceuticals from contaminated water up to 85.90% during 48 h. Then, the electro-Fenton (EF) method was applied for further removal of PhP yielding a removal rate of about 98.72% under optimum conditions during 2 h. The effects of variables including the current, amount of catalyst, and pH were also studied in this phase. Also, the probability of adsorption was investigated during this step. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis were performed for the used magnetite nanoparticles, total organic carbon (TOC) were performed to investigate PhP removal efficiency during the reaction time and Gas chromatography-mass spectrometry (GC-MS) were performed to analyze degradation byproducts of PhP. Based on the results, it was found that a combination of these bioremediation and electrochemical removal steps were capable of PhP removal from contaminated water. Therefore, this approach may be effective for phytoremediation of pharmaceutical-contaminated aquatic ecosystems.

Two-electron oxygen reduction on fullerene C60-carbon nanotubes covalent hybrid as a metal-free electrocatalyst.

Nanocarbon materials are considered to be active for electrochemical oxygen reduction reaction (ORR) for hydrogen peroxide (H2O2) synthesis. In the present work, a new type of fullerene 60 (C60)-carbon nanotubes (CNTs) hybrid with covalently attached C60 onto outer surface of CNTs was synthesized. The structure of C60-CNT hybrid was confirmed by physical and chemical characterizations and its conformation is proposed featuring the covalent incorporation of CNTs and C60 derivative. C60-CNT hybrid showed high efficiencies on electro-generating H2O2, owing to huge surface area and intermolecular electron-transfer in the hybrid structure. A high H2O2 production rate of 4834.57 mg L-1 h-1 (426.58 mmol L-1) was achieved at - 0.2 V vs saturated calomel electrode (SCE).

Photo-assisted electrochemical abatement of trifluralin using a cathode containing a C60-carbon nanotubes composite.

This work reports the potential application of modified gas-diffusion electrode (GDE) with C60-CNT composite, as a stable and efficient cathode material for degradation of trifluralin (TRL) pesticide by photo-assisted electrochemical (PE) process. C60-CNT composite was prepared and characterized. Subsequently, a novel C60-CNT composite modified GDE cathode was developed and the electrochemical and physical characteristics of the modified GDEs were studied. C60-CNT composite/GDE showed great efficiencies for electro-generating H2O2, owing to huge surface area and high conductivity. Afterwards, a comparative study of TRL oxidation via photolysis, anodic oxidation (AO) and PE processes using C60-CNT composite/GDE revealed the degradation percentages of 42.2, 48.5 and 93.4%, respectively, after 180 min of treatment. The TRL degradation followed a pseudo-first-order kinetics, being faster in the order: photolysis < AO < PE. The effects of various operational conditions were assessed on the degradation of TRL. From the results, PE process using C60-CNT composite/GDE exhibited great performance for the degradation of TRL (20 mg L-1) under its original pH, Na2SO4 electrolyte concentration of 0.05 mol L-1, applied current intensity of 300 mA, and flow rate of 12.5 L h-1. TOC results displayed that 92.8% of TRL was mineralized after 8 h of PE process. In addition, a plausible pathway for mineralization of TRL was proposed according to the identified by-products detected by means of gas chromatography-mass spectroscopy (GC-MS), High-performance liquid chromatography (HPLC) and ion chromatography analyses.

Kinetic modeling of sonocatalytic performance of Gd-doped CdSe nanoparticles for degradation of Acid Blue 5.

CdSe and Gd-doped CdSe nanoparticles were synthesized using a simple hydrothermal method, and their catalytic activity was examined toward degradation of Acid Blue 5 (AB5) in the sonocatalytic process. The structure and morphology of as-prepared nanomaterials were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Branauer, Emmett and Teller (BET) and Fourier infrared spectroscopy (FT-IR) techniques. Among the synthesized samples, 4% Gd-doped CdSe nanoparticles demonstrated the highest catalytic activity with band gap energy of 1.61eV. The effect of dopant content, initial dye concentration, catalyst dosage, ultrasonic power and inorganic radical scavengers on the degradation efficacy of AB5 was evaluated. The produced intermediates of AB5 degradation during sonocatalytic process were verified using gas chromatography-mass spectroscopy (GC-MS) technique. A novel intrinsic kinetic model for prediction of AB5 degradation efficiency was proposed. A good agreement was obtained between developed model and experimental data (R2>0.94).

One-step preparation of nanostructured martite catalyst and graphite electrode by glow discharge plasma for heterogeneous electro-Fenton like process.

Natural Martite ore particles and graphite were modified by alternating current (AC) glow discharge plasma to form nanostructured catalyst and cathode electrode for using in the heterogeneous-electro Fenton-like (Het-EF-like) process. The performance of the plasma-treated martite (PTM) and graphite electrode (PTGE) was studied for the treatment of paraquat herbicide in a batch system. 85.78% degradation efficiency for 20 mg L-1 paraquat was achieved in the modified process under desired operational conditions (i.e. current intensity of 300 mA, catalyst amount of 1 g L-1, pH = 6, and background electrolyte (Na2SO4) concentration of 0.05 mol L-1) which was higher than the 41.03% for the unmodified one after 150 min of treatment. The ecofriendly modification of the martite particles and the graphite electrode, no chemical needed, low leached iron and milder operational pH were the main privileges of plasma utilization. Moreover, the degradation efficiency through the process was not declined after five repeated cycles at the optimized conditions, which proved the stability of the nanostructured PTM and PTGE in the long-term usage. The archived results exhibit this method is the first example of high efficient, cost-effective, and environment-friendly method for generation of nanostructured samples.

A novel and sensitive chemosensor based on a KMnO4-rhodamine B-CdS quantum dot chemiluminescence system for meropenem detection.

A sensitive and simple flow injection chemiluminescence (CL) system was constructed for the determination of meropenem, in which the CL intensity of the KMnO4-rhodamine B (Rh B) reaction was enhanced in the presence of CdS quantum dots (QDs). A CL resonance energy transfer (CRET) occurs between CdS QDs as a donor and Rh B as an energy acceptor. Based on the strong specific quenching effect of meropenem on the CL intensity, a novel chemosensor for meropenem sensing was developed. Under the optimized conditions, the quenched CL emission intensity was proportional to the concentration of meropenem in the range of 0.002-10.0 mg L-1 with a detection limit (3σ) of 0.8 µg L-1 Moreover, the feasibility of the induced CL system was studied via the meropenem determination in environmental water samples.

A simple and sensitive flow injection method based on the catalytic activity of CdS quantum dots in an acidic permanganate chemiluminescence system for determination of formaldehyde in water and wastewater.

A simple and sensitive flow injection chemiluminescence (CL) method in which CdS quantum dots (QDs) enhanced the CL intensity of a KMnO4-formaldehyde (HCHO) reaction was offered for the determination of HCHO. This CL system was based on the catalytic activity of CdS QDs and their participation in the CL resonance energy transfer (CRET) phenomenon. A possible mechanism for the supplied CL system was proposed using the kinetic curves of the CL systems and the spectra of CL, photoluminescence (PL) and ultraviolet-visible (UV-Vis). The emanated CL intensity of the KMnO4-CdS QDs system was amplified in the presence of a trace level of HCHO. Based on this enhancement effect, a simple and sensitive flow injection CL method was suggested for the determination of HCHO concentration in environmental water and wastewater samples. Under selected optimized experimental conditions, the increased CL intensity was proportional to the HCHO concentration in the range of 0.03-4.5 µg L(-1) and 4.5-10.0 µg L(-1). The detection limits (3σ) were 0.0003 µg L(-1) and 1.2 µg L(-1). The relative standard deviations (RSD%) for eleven replicate determinations of 4.0 µg L(-1) HCHO were 2.2%. Furthermore, the feasibility of the developed method was investigated via the determination of HCHO concentration in environmental water and wastewater samples.

Enhanced chemiluminescence of carminic acid-permanganate by CdS quantum dots and its application for sensitive quenchometric flow injection assays of cloxacillin.

A novel chemiluminescence (CL) system is introduced based on the oxidation of carminic acid by KMnO4 in acidic conditions. CdS quantum dots (QDs) were synthesized using a facile hydrothermal method which efficiently enhanced the intensity of the CL system. A possible mechanism for the proposed system is presented using the kinetic curves, CL spectra, photoluminescence (PL), and ultraviolet-visible (UV-Vis) analysis. The emission intensity of the KMnO4-carminic acid-CdS QDs system was quenched in the presence of a trace level of cloxacillin. Based on this quenching effect, a novel and sensitive flow injection CL method was developed for determining cloxacillin concentrations. At optimal experimental conditions, the decreased CL intensity had a good linear relation with the cloxacillin concentration in the range of 0.008 to 22.0 mg L(-1). The detection limit (3σ) was 5.8 µg L(-1). The precision of the method was calculated by analyzing samples containing 4.0 mg L(-1) of cloxacillin (n=11), and the relative standard deviations (RSD%) were 2.08%. The feasibility of the method is also demonstrated for determining cloxacillin concentrations in environmental water samples and a pharmaceutical formulation.

Flow-injection chemiluminescence analysis for sensitive determination of atenolol using cadmium sulfide quantum dots.

A sensitive, rapid and simple flow-injection chemiluminescence (CL) system based on the light emitted from KMnO4-cadmium sulfide quantum dots (CdS QDs) reaction in the presence of cetyltrimethylammonium bromide (CTAB) in acidic medium was developed as a CL probe for the sensitive determination of atenolol. Optical and structural features of CdS QDs capped with l-cysteine, which synthesized via hydrothermal approach, were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL), and UV-Vis spectroscopy. The CL intensity of KMnO4-CdS QDs-CTAB was remarkably enhanced in the presence of trace level of atenolol. Under optimum experimental conditions, there is a linear relationship between the increase in CL intensity of KMnO4-CdS QDs-CTAB system and atenolol concentration in a range of 0.001 to 4.0 mg L(-1) and 4.0 to 18.0 mg L(-1), with a detection limit (3σ) of 0.0010 mg L(-1). A possible mechanism for KMnO4-CdS QDs-CTAB-atenolol CL reaction is proposed. To prove the practical application of the KMnO4-CdS QDs-CTAB CL method, the method was applied for the determination of atenolol in spiked environmental water samples and commercial pharmaceutical formulation. Furthermore, corona discharge ionization ion mobility spectrometry (CD-IMS) technique was utilized for determination of atenolol.

A flow injection chemiluminescence method for determination of nalidixic acid based on KMnO4-morin sensitized with CdS quantum dots.

A simple and sensitive flow injection chemiluminescence (CL) method was developed for determination of nalidixic acid by application of CdS quantum dots (QDs) in KMnO4-morin CL system in acidic medium. Optical and structural features of L-cysteine capped CdS quantum dots which were synthesized via hydrothermal approach were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL), and ultraviolet-visible (UV-Vis) spectroscopy. Moreover, the potential mechanism of the proposed CL method was described using the results of the kinetic curves of CL systems, the spectra of CL, PL and UV-Vis analyses. The CL intensity of the KMnO4-morin-CdS QDs system was considerably increased in the presence of nalidixic acid. Under the optimum condition, the enhanced CL intensity was linearly proportional to the concentration of nalidixic acid in the range of 0.0013 to 21.0 mg L(-1), with a detection limit of (3σ) 0.003 mg L(-1). Also, the proposed CL method was utilized for determination of nalidixic acid in environmental water samples, and commercial pharmaceutical formulation to approve its applicability. Furthermore, corona discharge ionization ion mobility spectrometry (CD-IMS) method was utilized for determination of nalidixic acid and the results of real sample analysis by two proposed methods were compared. Comparison the analytical features of these methods represented that the proposed CL method is preferable to CD-IMS method for determination of nalidixic acid due to its high sensitivity and precision.

Comparison of two methods for selegiline determination: A flow-injection chemiluminescence method using cadmium sulfide quantum dots and corona discharge ion mobility spectrometry.

Two analytical approaches including chemiluminescence (CL) and corona discharge ionization ion mobility spectrometry (CD-IMS) were developed for sensitive determination of selegiline (SG). We found that the CL intensity of the KMnO4-Na2S2O3 CL system was significantly enhanced in the presence of L-cysteine capped CdS quantum dots (QDs). A possible CL mechanism for this CL reaction is proposed. In the presence of SG, the enhanced CL system was inhibited. Based on this inhibition, a simple and sensitive flow-injection CL method was proposed for the determination of SG. Under optimum experimental conditions, the decreased CL intensity was proportional to SG concentration in the range of 0.01 to 30.0 mg L(-1). The detection limit (3σ) was 0.004 mg L(-1). Also, SG was determined using CD-IMS, and under optimum conditions of CD-IMS, calibration curves were linear in the range of 0.15 to 42.0 mg L(-1), with a detection limit (3σ) of 0.03 mg L(-1). The precision of the two methods was calculated by analyzing samples containing 5.0 mg L(-1) of SG (n=11). The relative standard deviations (RSDs%) of the flow-injection CL and CD-IMS methods are 2.17% and 3.83%, respectively. The proposed CL system exhibits a higher sensitivity and precision than the CD-IMS method for the determination of SG.

Determination of dexamethasone by flow-injection chemiluminescence method using capped CdS quantum dots.

L-Cysteine capped CdS quantum dots (QDs) were synthesized through a facile hydrothermal method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL) and UV-Vis spectroscopy. The light emitted from KMnO4-L-cysteine capped CdS QDs reaction in acidic medium was applied as a simple and sensitive chemiluminescence (CL) system for determination of dexamethasone. The CL intensity of KMnO4-L-cysteine capped CdS QDs CL system was remarkably enhanced in the presence of dexamethasone. Under optimum experimental conditions, the enhanced CL intensity was related to dexamethasone concentration in the range of 0.004-25.0 mg L(-1), with the detection limit (3σ) of 0.0013 mg L(-1). The analytical applicability of the proposed CL system was assessed by determining dexamethasone in spiked environmental water samples and pharmaceutical formulation. The analytical performances of proposed flow-injection CL method for the determination of dexamethasone were compared with those obtained by corona discharge ionization ion mobility spectrometry (CD-IMS) method. The proposed CL system exhibits a higher sensitivity and precision than the CD-IMS method for the determination of dexamethasone.