Current development and future challenges in microplastic detection techniques: a bibliometrics-based analysis and review.

Microplastics have been considered a new type of pollutant in the marine environment and have attracted widespread attention worldwide in recent years. Plastic particles with particle size less than 5 mm are usually defined as microplastics. Because of their similar size to plankton, marine organisms easily ingest microplastics and can threaten higher organisms and even human health through the food chain. Most of the current studies have focused on the investigation of the abundance of microplastics in the environment. However, due to the limitations of analytical methods and instruments, the number of microplastics in the environment can easily lead to overestimation or underestimation. Microplastics in each environment have different detection techniques. To investigate the current status, hot spots, and research trends of microplastics detection techniques, this review analyzed the papers related to microplastics detection using bibliometric software CiteSpace and COOC. A total of 696 articles were analyzed, spanning 2012 to 2021. The contributions and cooperation of different countries and institutions in this field have been analyzed in detail. This topic has formed two main important networks of cooperation. International cooperation has been a common pattern in this topic. The various analytical methods of this topic were discussed through keyword and clustering analysis. Among them, fluorescent, FTIR and micro-Raman spectroscopy are commonly used optical techniques for the detection of microplastics. The identification of microplastics can also be achieved by the combination of other techniques such as mass spectrometry/thermal cracking gas chromatography. However, these techniques still have limitations and cannot be applied to all environmental samples. We provide a detailed analysis of the detection of microplastics in different environmental samples and list the challenges that need to be addressed in the future

Cobalt oxide, sulfide and phosphide-decorated carbon felt for the capacitive deionization of lead ions

Remediation and recovery of highly toxic lead ions are highly important for water purification. In this study, a simple two-step method is developed to obtain the cobalt phosphide-decorated active carbon felt (ACF-CoP) materials for capacitive deionization of dilute Pb2+ (50 mg/L). The as-prepared ACF-CoP materials exhibit higher capacitance of 182.4 F/g than the corresponding ones of pristine ACF, ACF-CoS and ACF-Co3O4, which is possibly due to the surface Co3+ groups and abundant defect sites. Therefore, the Pb2+ ions were successfully recovered with an effective capacity of 90 mg/g at low voltage of -0.6 V. Furthermore, great charge/discharge stability and large voltage application range were also achieved in the as-fabricated ACF-CoP materials

High-Performance Capacitive Deionization of Copper Ions at Nanoporous ZnS-Decorated Carbon Felt

Extraction of dilute copper ions from wastewater is of great importance for simultaneous remediation of heavy-metal pollution and recovery of valuable metals. In this study, an efficient and selective method for copper recovery using capacitive deionization on ZnS-decorated carbon felt electrodes was developed and found suitable for use in HCl electrolytes. With the introduction of ZnS, the modified electrode exhibited a nanoporous structure with enhanced electrochemical capacitance, increased surface area and improved wettability. As a result, the copper ions were successfully removed via electrostatic interactions at low voltages of -0.2 V, in which the removal capacity of 27.4 mg.g(-1) is much better than the corresponding ones of FeS-decorated (18 mg.g(-1)) and pristine (12 mg.g(-1)) carbon felts. In addition to improved performance, enhanced adsorption-desorption stability and selectivity were observed during long-term tests in the presence of co-existing metallic ions and natural organic matter, offering promising potential as an alternative metal recycling and water purification technique. (C) 2019 The Electrochemical Society

Application of Klebsiella oxytoca Biomass in the Biosorptive Treatment of PAH-Bearing Wastewater: Effect of PAH Hydrophobicity and Implications for Prediction

Biosorption has been widely recognized as a promising method to treat wastewater. However, few studies have investigated the impact of pollutants’ properties on wastewater treatment, as well as the underlying mechanisms and future predictions. In this study, the effects of pollutants’ hydrophobicity on the biosorptive removal of polycyclic aromatic hydrocarbons (PAHs) were evaluated. The results showed that the inactive biomass of Klebsiella oxytoca effectively removes PAHs from aqueous solutions with a high biosorption capacity, high biosorption affinity, and short equilibrium time. The biosorption of seven PAHs achieved equilibrium rapidly (less than 2 h) and fitted well to the pseudo-second-order kinetic model. Sorption occurred with a predominantly linear partition process to the biomaterial with Kd values of 363.11, 1719.5, 2515.5, 7343.3, 6353.4, 22,806, and 19,541 L·kg−1 for naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, pyrene, and fluoranthene, respectively. An increase in temperature led to a decrease in the biosorption affinity, and the bacterial biosorption of PAHs was spontaneous and exothermic. Furthermore, a positive correlation was observed between the sorption affinity and the octanol partition coefficient (Kow) (logKd = 1.011logKow − 0.7369), indicating that hydrophobicity is the main factor influencing the biosorption efficiency. These results suggest that biosorption is an efficient and predictable treatment for micropollutant-bearing wastewater

Thermal behavior and kinetic study on the co-pyrolysis of biomass with polymer waste

The intrinsic smaller hydrogen to carbon (H/C) ratio for lignocellulosic biomass significantly affects the yield and production of target products. Co-pyrolyzing of biomass with hydrogen-rich chemicals or raw materials offers an alternative pathway to improve the H/C ratio of feedstock and thus upgrade the bio-oils. In this work, the co-pyrolysis of rice husk (RH) with epoxy resin (ER) was attempted, and its kinetic was comprehensively studied using the model-free and model-fitting methods. The co-pyrolysis mechanism and kinetic compensation effects were probed as well. The thermogravimetric analysis indicated that the decomposition of RH-ER blend with a weight ratio of 1:1 can be divided into three stages with heating temperatures of 27-270, 270-500, and 500-850 degrees C and corresponding mass loss of 6.86, 49.30, and 5.60%, respectively. For the model-free models applied, the activation energies (Ea) displayed an uptrend in the degree of conversion (alpha) range of 0.05-0.2 and a downtrend in alpha range of 0.2-0.6. Comparing the six methods, the Ea values from Friedman method was significantly larger than those from other models. The Flynn-Wall-Ozawa (FWO) method was more reliable with higher correlation coefficients. The obtained Ea values gradually increased from 65.06 to 159.55 kJ/mol (0.05 <= alpha <= 0.20) and then decreased to 38.32 kJ/mol (0.2 < alpha <= 0.60). The Ea values calculated based on three-dimensional diffusion (Jander equation) was comparable to that from the FWO method and could be responsible for the co-pyrolysis mechanism for RH-ER blend. An excellent linear relationship lnA = 0.2058Ea - 2.63095 can be observed, indicating that the compensation effect existed between the Ea and lnA during RH and ER co-pyrolysis. The pre-exponential factor (A) was determined as 2.9E8 min(-1) using the average Ea value of 107.48 kJ/mol. Through this study, it is expected to promote the collaborative disposal of multisource solid waste

Thermochemical conversion of waste printed circuit boards: Thermal behavior, reaction kinetics, pollutant evolution and corresponding controlling strategies

With the rapid development of the global electronics industry, waste printed circuit boards (WPCBs) has become one of the world's fastest growing waste streams. Exploring an environmentally sound treatment for this abundant and multi-component waste is critical to its sustainable development. This study has been aimed to cover thermochemical conversion of WPCBs (combustion, pyrolysis, gasification and hydrothermal process), focusing on thermal behavior, reaction kinetics, pollutant evolution and corresponding controlling strategies, with the aim of promoting circular economic development and building a sustainable future for the electronics industry.This work was financially supported by the Zhejiang Provincial Natural Science Foundation of China (Grant no. LTY21B070002). R. Luque gratefully acknowledges Universitá degli studi Mediterranea di Reggio Calabria (DICEAM) for his current Rosario Pietropaolo Honorary Chair

Hypoxia-induced miR-497 decreases glioma cell sensitivity to TMZ by inhibiting apoptosis

AbstractUnderstanding the resistance of glioma cells to chemotherapy has been an enormous challenge. In particular, mechanisms by which tumor cells acquire resistance to chemotherapy under hypoxic conditions are not fully understood. In this study, we have found that miR-497 is overexpressed in glioma and that hypoxia can induce the expression of miR-497 at the transcriptional level by binding with the hypoxia response element in the promoter. Ectopic overexpression of miR-497 promotes chemotherapy resistance in glioma cells by targeting PDCD4, a tumor suppressor that is involved in apoptosis. In contrast, the inhibition of miR-497 enhances apoptosis and increases the sensitivity of glioma cells to TMZ. These results suggest that miR-497 is a potential molecular target for glioma therapy

Response of fungal composition and diversity to simulated nitrogen deposition and manipulation of precipitation in soils of an Inner Mongolia desert steppe of Northern China

Nitrogen deposition (N) and precipitation changes can strongly influence soil microbial properties in arid and semiarid regions. Here, we examined these effects on soil samples from the Inner Mongolia desert steppe of northern China after 7 years of consecutive simulated nitrogen deposition by adding NH4NO3 and manipulation of precipitation, using a dilution plate method, PCR, and 18S rRNA sequencing. The experimental treatments were as follows: control (CK), N addition (+N), N and water addition (+N+W), and N addition plus water reduction (+N−W). In this study, 14 genera and 32 fungal species were isolated, and Penicillium determined to be the dominant fungal group. Treatment +N−W significantly increased (by 94.8%) the number of cultivable fungi as compared with CK. Compared with the CK community, fungal communities exposed to the three treatments, especially +N+W and +N−W, showed shifts in the relative abundances of cultivable fungi. Treatment +N−W significantly enhanced species richness compared to +N at 0–2 cm soil depth. However, N addition and manipulation of precipitation did not influence species richness, the Shannon-Weiner index (H′), or evenness (E) at 0–30 cm soil depth. This study can provide insight into how fungal composition and diversity respond to climate change scenarios.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author