Radwan A. Almasri, Nasser AM Barakat, Osama M Irfan
Background
Recently, the concept of the membrane-less microbial fuel cell (MFC) has gained traction to avoid the high internal resistance that is created upon utilizing conventional membranes. Nevertheless, an overlooked problem arises from the ingress of oxygen from the cathode side into the anolyte solution, fostering the formation of biofilms by aerobic microorganisms on the cathode surface. This biofilm layer poses a formidable impediment, leading to cell disconnection. Moreover, low surface area of conventional anodes is another important issue behind the low power density generation. In this research, a novel approach to circumvent biofilm formation and achieve stable and high-power-density output from MFCs by harnessing a commercial antibacterial spacer is introduced.
Results
Air-cathode, sewage-driven MFCs showed continuous power generation without the need for external microorganisms. Conversely, the absence of the innovative membrane resulted in a catastrophic power breakdown after 125 h of operation due to the formation of a dense biofilm layer on the cathode. Through the utilization of the proposed membrane strategy, stable power density output of 100 ± 8, 135 ± 11 and 142 ± 10 mW m−2 with carbon cloth, carbon paper and carbon felt anodes, respectively, was achieved. Moreover, a novel anode is introduced from graphitization of grape tree branches. The proposed anode could increase the generated power to 516 ± 17 mW m−2 from the sewage-driven air-cathode MFC, more than three times compared to the best conventional anode, carbon felt.
Jinyun Song, Runying Bai, Bo Wu, Ruzhuang Zhang, Yuchao Yang, Yi Ding, Hexin Zhu, Haoxiang Yang, Siyu Zhao
BACKGROUND
With the increasing global demand for food, a significant amount of organophosphorus pesticides is applied to farmland, leading to pollution as they are discharged into natural water bodies with agricultural runoff. This study employed a coupling approach, utilizing a 6:4 mass ratio of zirconium-based metal–organic framework UiO-66 and g-C3N4 through a grinding and annealing method to construct a Z-type heterojunction composite material named UG 6:4.
RESULTS
This material is employed for photocatalytic removal of the representative organophosphorus pesticide, dichlorvos (DDVP), from water and simultaneous in situ adsorption of its inorganic phosphorus byproducts. Results demonstrate that for initial DDVP concentrations below 5 mg L−1 (calculated as total phosphorus), both the mineralization rate under ultraviolet light irradiation with a wavelength of 365 nm and a power of 125 W and the adsorption rate of phosphorus were 100% when the pH was 6 and the UG 6:4 dosage was 0.2 g L−1. The sheet-like g-C3N4 tightly envelops the surface of UiO-66, forming a Z-scheme heterojunction. This structure imparts UG 6:4 with enhanced light absorption, faster generation and separation of photogenerated electron–hole pairs compared to individual UiO-66 or g-C3N4, and the establishment of an internal electric field suppresses the recombination of photogenerated charge carriers.
Solid-state fermentation (SSF) has gained attention recently as a promising approach for producing a range of high-value industrial products. SSF has several benefits, including a high product yield, a lesser chance of contamination, a resemblance to some fungi and bacteria's native environment, a lower energy need, and cost-effectiveness. Additionally, the enzyme extraction from concentrated solutions facilitates the recovery procedure. Mucor racemosus, a filamentous fungus, has the potential to produce a milk-clotting enzyme (aspartic protease) cultivated on various combinations of the solid media to investigate the effect of media on the production and activity of the milk-clotting enzyme.
RESULTS
The fermentation was scaled up by utilizing Terrafors-IS Infors HT in-situ sterilizable rotating solid-state bioreactor to cultivate the fungus. The effect of agitation (rotation on the day of inoculation and day 1), aeration (air flow rates of 1 L and 2 L/min), and moisture content (60% and 90%), during SSF were investigated. The profiles of various operational parameters (that is, temperature, pressure, flow rate, exit O2, and exit CO2) were monitored using the provided software, and data were collected at 10-min intervals during the whole course of fermentation. The results suggest that aeration has a remarkable effect on the quantity of biomass produced, but it doesn't assure high enzyme production. The highest milk clotting activity of ~570 U/mL was recorded with a moisture content of 60% and a flow rate of 1 L/min.
Chengjie Li, Yinghui Mo, Liang Wang, Heng Guo, Xiaoxue Ji
BACKGROUND
Printing and dyeing reverse osmosis concentrates (ROC) contain large amounts of salts and organic matter, which is a major environmental issue. The unique composition of such wastewater makes the use of traditional physicochemical techniques challenging.
RESULTS
In this paper, titanium dioxide nanotube arrays/SnO2-Sb2O3 (Ti-NTA/SnO2-Sb2O3) electrodes were prepared by anodizing–cathodizing and sol–gel method for the electrocatalytic degradation of printing and dyeing ROC. Organic matter removal under different situations was examined, and the best treatment parameters were identified.
Cui Quan, Yingying Zhou, Hua Chu, Xiaolei Fan, Ningbo Gao
BACKGROUND
Ethyl lactate produced via esterification between lactic acid and ethanol can be used in plastics, polymers and food industries and renowned for its biodegradability and low toxicity. However, lactic acid self-catalyzed esterification presents a slow reaction process, and acid catalysts are needed to improve the catalysis. Homogeneous acid catalysts like H2SO4 are corrosive, as well as being difficult to be seperated from the reaction media; therefore, advanced heterogeneous catalysts are more ideal. In this study, two kinds of heteropolyacid–zeolite catalysts, involving loading silicotungstic acid and phosphotungstic acid onto Y zeolite, were synthesized, characterized using X-ray diffraction, NH3 temperature-programmed desorption and scanning electron microscopy and analyzed for their catalytic efficiency in the catalytic esterfication.
RESULTS
Results showed that the Keggin structures of heteropolyacids were retained during the preparation process and strong acid sites of Y zeolite were enriched, which made the main contribution to the esterification of lactic acid and ethanol. Furthermore, the initial-stage reaction rate of esterification was significantly enhanced. During the first hour of esterification, the conversion of lactic acid increased from 18% to 65%. Exp Dec1 index model was employed to determine the activation energies of 60HSiW-Y and 60HPW-Y, which exhibit values of 29.3 and 28.2 kJ mol−1, respectively.
A microalgae–bacteria consortium applied to the treatment of domestic wastewater can be an alternative to reduce the energy consumption of aerobic systems if the algal biomass produces enough oxygen for bacterial consumption. This study proposed to evaluate the microalgal production of photosynthetic O2 and consumption by heterotrophic organic matter-removing and autotrophic nitrifying bacteria through respirometric tests.
RESULTS
Aggregates composed of predominantly spherical green microalgae and bacteria were formed in a photosequencing batch reactor, with 6 h cycles, and fed with synthetic domestic wastewater. Biomass reached 800 mgVSS L−1 and chlorophyll-a content of 4 mg gVSS−1. Photosynthetic oxygen production reached 33.4 mgO2 gSS−1 h−1. Through respirometric tests and oxygen mass balance, oxygen consumption rates by ordinary heterotrophic bacteria (5.9 mgO2 gSS−1 h−1), ammonia-oxidizing bacteria (8.67 mgO2 gSS−1 h−1) and nitrite-oxidizing bacteria (0.78 mgO2 gSS−1 h−1) were obtained.
Adsorption is a widely used technique for separating impurities in various industries. This method offers flexibility in design and operation and results in the production of high-quality purified wastewater. This experimental research investigates the effectiveness of carbon-based adsorbents, such as graphene, graphene oxide and carbon dots, in removing impurities and increasing hydrogen peroxide concentration through adsorption.
RESULTS
Various characterization techniques were used to investigate each adsorbent's chemical properties and surface morphology, including Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy and Brunauer–Emmett–Teller analysis. According to adsorption tests under the defined conditions, the synthesized graphene showed the highest efficiency in impurities removal from hydrogen peroxide, with purity level of 45%. Graphene showed higher efficiency than graphene oxide and carbon dot samples, with a purity of 36% and 32%, respectively. Various factors, such as time, temperature and adsorbent dosage, were investigated at different stages of the experiments. The results show that the adsorption of impurities on carbon-based adsorbents is an exothermic process.
Agarwal, H., Thwin, C., & Kumaar, B. T. (2023). Single-use centrifugal separator enables intensification of the clarification process in biomanufacturing of recombinant proteins. Journal of Chemical Technology & Biotechnology, 98(5), 1321–1332.
In Table 3, under the column Scenario B and row Bioreactor viability (%), instead of ≥80%, it should be <80%.
{"title":"Correction to “Single-use centrifugal separator enables intensification of the clarification process in biomanufacturing of recombinant proteins”","authors":"","doi":"10.1002/jctb.7760","DOIUrl":"https://doi.org/10.1002/jctb.7760","url":null,"abstract":"<p>\u0000 <span>Agarwal, H.</span>, <span>Thwin, C.</span>, & <span>Kumaar, B. T.</span> (<span>2023</span>). <span>Single-use centrifugal separator enables intensification of the clarification process in biomanufacturing of recombinant proteins</span>. <i>Journal of Chemical Technology & Biotechnology</i>, <span>98</span>(<span>5</span>), <span>1321</span>–<span>1332</span>.</p><p>In Table 3, under the column <i>Scenario B</i> and row <i>Bioreactor viability (%)</i>, instead of ≥80%, it should be <80%.</p><p>We apologize for this error.</p>","PeriodicalId":15335,"journal":{"name":"Journal of chemical technology and biotechnology","volume":"100 1","pages":"286"},"PeriodicalIF":2.8,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jctb.7760","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142861379","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号