Inorganic Processes Research Articles

Analysis of Controlling Factors of Pore Structure in Different Lithofacies Types of Continental Shale—Taking the Daqingzi Area in the Southern Songliao Basin as an Example

Due to the influence of terrigenous debris, the internal pore structure of continental shale is highly heterogeneous, and the controlling factors are complex. This paper studies the structure and controlling factors of shale reservoirs in the first member of the Qingshankou Formation in the Southern Songliao Basin using core data and various analytical test data. The results show that the original deposition and subsequent diagenesis comprehensively determine the shale reservoirs’ pore structure characteristics and evolution law. According to the severity of terrigenous debris, the shale reservoirs in the study area are divided into four categories and six subcategories of lithofacies. By comparing the characteristics of different shale lithofacies reservoirs, the results show that the lithofacies with a high brittle mineral content have more substantial anti-compaction effects, more primary pores to promote retention and a relatively high proportion of mesopores/macropores. Controlling the organic matter content when forming high-quality reservoirs leads to two possibilities. An excessive organic matter content will fill pores and reduce the pore pressure resistance. A moderate organic matter content will make the inorganic diagenesis and organic hydrocarbon generation processes interact, and the development of organic matter mainly affects the development of dissolution pores. The comprehensive results show that A3 (silty laminated felsic shale) reservoirs underwent the pore evolution process of “two drops and two rises” of compaction, cementation and pore reduction, dissolution and pore increase, and organic matter cracking and pore increase, and they are the most favourable lithofacies of the shale reservoirs in the study area.

Metal‐Supported Heterogeneous Catalysts for the Synthesis of Nitrogen‐Containing Heterocycles: A Comprehensive Review

AbstractThe use of metals in the preparation of heterocycles has become increasingly popular due to several key advantages of metals as catalysts. These include recycling capability, eco‐friendliness, simplicity of catalyst preparation and separation, longer lifespan, abundance, and higher yields. As a result of their novel applications in organic, inorganic, medicinal, industrial, polymer chemistry, material sciences, nanotechnology, and biological processes, the utilization of nitrogen‐containing heterocycles has rapidly increased in recent years. Various nitrogen‐containing organic moieties are used in therapeutic processes to enhance effectiveness against several bacterial and viral diseases. This review covers the preparation of imidazoles, triazoles, tetrazoles, pyridine derivatives, azo compounds, pyrimidines, quinoxalines, and quinolines using metals as heterogeneous catalysts. It provides an overview of current methodologies for metal‐assisted heterogeneous catalytic reactions, including product yield, operating temperature, and solvents, among other factors. Heterogeneous catalyst‐mediated organic synthetic reactions offer several advantages, particularly in medicinal chemistry, pharmaceuticals, and industrial applications, by reducing time and energy consumption. This review emphasizes recent advancements in the fabrication of nitrogen heterocycles utilizing heterogeneous catalysts, taking into account various economic, eco‐friendly, and user‐friendly considerations. Additionally, it discusses the benefits, reaction conditions, and yields reported in the literature over the past six years.

Advancements in Inorganic Membrane Filtration Coupled with Advanced Oxidation Processes for Wastewater Treatment.

Membrane filtration is an effective water recycling and purification technology to remove various pollutants in water. Inorganic membrane filtration (IMF) technology has received widespread attention because of its unique high temperature and corrosion resistance. Commonly used inorganic membranes include ceramic membranes and carbon-based membranes. As novel catalytic inorganic membrane processes, IMF coupled with advanced oxidation processes (AOPs), can realize the separation and in situ degradation of pollutants, thus mitigating membrane contamination. In this paper, the types and performance of IMF are discussed. The influencing factors of inorganic membranes in practical wastewater treatment are summarized. The applications, advantages, and disadvantages of the coupled process of IMF and AOPs are summarized and outlined. Finally, the challenges and prospects of IMF and IMF coupled with AOPs are presented, respectively. This contributes to the design and development of coupled systems of membrane filtration with inorganic materials and IMF coupled with AOPs for practical wastewater treatment.

Crucial role of extracellular polymeric substances from anammox sludge in wastewater phosphorus recovery via magnesium phosphate crystallization

The magnesium phosphate (Mg-P) crystallization based on anaerobic ammonia oxidation is of interest for simultaneous nitrogen and phosphorus removal in wastewater treatment due to cost-effectiveness. Understanding the role of extracellular polymeric substances (EPS) in crystal growth is pivotal for bio-induced Mg-P crystallization. In this work, the effects of EPS in Mg-P crystallization were thoroughly investigated. Results indicated that EPS decreased the initial crystallization rate but slightly improved the final crystallization yield. The maximum removal efficiencies of Mg and P ions increased by 2.8 % and 3.1 %, respectively, when EPS concentration was 80 mg/L. Additionally, the presence of EPS enhanced Mg3(PO4)2·10 H2O production and facilitated the formation of larger rhombic plate-like structures crystals (maximum particle size increased by 215 %). Analysis of EPS composition changes during the crystallization process and characterization of the final crystals suggested that tryptophan-like proteins preferentially involved in the Mg-P crystallization process, while β-sheet proteins potentially influencing crystal morphology. Furthermore, the formation of phosphate ester groups, hydrogen bonding, and COOH-Mg2+ complexes were considered triggering factors for the interaction between EPS and Mg-P crystals. This study elucidated the underlying mechanism of EPS on Mg-P crystallization, further enhancing the understanding of the interaction between inorganic mineralization processes and microorganisms.

Constraining sulfur incorporation in calcite using inorganic precipitation experiments

The sulfur over calcium ratio (S/Ca) in foraminiferal shells was recently proposed as a new and independent proxy for reconstructing marine inorganic carbon chemistry. This new approach assumes that sulfur is incorporated into CaCO3 predominantly in the form of sulfate (SO42−) through lattice substitution for carbonate ions (CO32–), and that S/Ca thus reflects seawater [CO32–]. Although foraminiferal growth experiments validated this approach, field studies showed controversial results suggesting that the potential impact of [CO32–] may be overwritten by one or more parameters. Hence, to better understand the inorganic processes involved, we here investigate S/Ca values in inorganically precipitated CaCO3 (S/Ca(cc)) grown in solutions of CaCl2 − Na2CO3 − Na2SO4 − B(OH)3 − MgCl2. Experimental results indicate the dependence of sulfate partitioning in CaCO3 on the carbon chemistry via changing pH and suggest that faster precipitation rates increase the partition coefficient for sulfur. The S/Ca ratios of our inorganic calcite samples show positive correlation with modelled [CaSO40](aq), but not with the concentration of free SO42− ions. This challenges the traditional model for sulfate incorporation in calcite and implies that the uptake of sulfate potentially occurs via ion-ion pairs rather than being incorporated as single anions. Based on the [Ca2+] dependence via speciation, we here suggest a critical evaluation of this potential proxy. As sulfate complexation seems to control sulfate uptake in inorganic calcite, application as a proxy using foraminiferal calcite may be limited to periods for which seawater chemistry is well-constrained. As foraminiferal calcite growth is modulated by inward Ca2+ flow to the site of calcification coupled to outward H+ pumping, sulfate incorporation as CaSO40 ion-pair in the foraminifer’s shell also provides a mechanistic link for the observed relationship between S/Ca(cc) and [CO32–].

Effect of zirconia as inorganic binder on molds for precision casting

AbstractSand‐casting molds suffer from surface defects and low strength. An organic–inorganic binder conversion process, wherein an organic binder is converted to an inorganic binder, has been proposed to increase the application temperature of the sand‐casting mold and simplify the manufacturing process for precision casting. However, the usable temperature of the typical SiO2–Na2O binder system is limited to approximately 1000°C owing to the low liquefaction temperature of the compound. The resulting glass phase (Na2SiO3) exhibits low viscosity, and the casting of large objects results in low strength. Therefore, in this study, we propose a SiO2–Na2O–ZrO2 ternary inorganic binder system; the addition of zirconia (ZrO2) into sodium silicate (Na2SiO3) as an inorganic binder was expected to increase the operating temperature of the mold and improve its mechanical properties. The results confirmed that the addition of ZrO2 improved the mechanical properties by preventing the formation of Na2SiO3. In addition, a higher sintering temperature corresponded to smaller and larger amounts of Na2SiO3 and Na2ZrSiO5, respectively, and thus a higher strength. Therefore, we expect our developed ternary inorganic binder system to be highly advantageous for producing molds for high‐temperature and precision casting.

P-doped Mo2C nanoparticles embedded on carbon nanofibers as an efficient electrocatalyst for Li-S batteries

Designing a reliable sulfur host that can simultaneously catalyze sulfur redox reactions and suppress polysulfides shuttling is highly desired for the development of advancing Li-S batteries. In this work, P-doped Mo2C nanoparticles anchoring on carbon nanofibers (CNF) is prepared via an organic–inorganic nanohybridization process. The interwoven CNF networks establish continuous electrons transport pathways and provide a large surface area for loading P-Mo2C nanoparticles. The P dopant tunes the electronic structure of Mo2C, which endows P-Mo2C with enhanced polysulfides adsorption ability and improved sulfur redox kinetics. Leveraging these advantages, the Li-S battery shows excellent electrochemical properties, delivering a high specific capacity of 1174 mA·h·g−1 at 0.2 C, and maintaining over 1200 stable cycles at 1 C with a low capacity attenuation rate of 0.043 % per cycle. At a S loading of 4.88 mg·cm−2 and E/S ratio of 8.25 μL·mg−1, the Li-S battery attains an areal capacity of 6.50 mA·h·cm−2 at 0.05 C. These results highlight the promising application potential of P-Mo2C@CNF as an effective electrocatalyst for Li-S batteries.

To what extent do geopolitical conditions affect the environmental sustainability of the circular economy? A comparative LCA study of lactic acid production in Denmark and Iran

Transitioning to a circular economy is inevitable in well-developed and developing economies. Biowaste valorization into value-added products has shown a promising sustainable solution compared to its fossil-based counterparts. However, it has yet to be scientifically analyzed to what extent geopolitical conditions affect the environmental sustainability of the circular economy. To fill this gap, we conducted a consequential life cycle assessment of biorefining biowaste into lactic acid and bioenergy in Denmark and Iran as representative examples of developed and developing economies, respectively. Despite the notable environmental impacts associated with fossil-based energy consumption and infrastructural limitations, Iran could benefit more environmentally from the suggested biorefinery by 2030 than Denmark. This contrast arises from the fact that the existing dominant waste management solution in Iran consists of sanitized and unsanitized landfills, which appear likely to continue through 2030. Therefore, any alternative waste management scenario would help avoid the environmental impacts arising from landfills. In contrast, Denmark already has a well-established and sustainable waste management practice for biowaste, namely anaerobic digestion. Accordingly, the environmental impacts of the investigated scenarios in Denmark were, on average, 85 %, 855 %, 177 %, and 130 % higher than those in Iran regarding resource scarcity, ecosystem quality, human health, and climate change, respectively. In both countries, incineration, the culture medium, ion exchange, vacuum distillation, transportation, emissions from digestate applications on farmlands, and the inorganic waste landfilling process (only applied to IR scenarios) contributed most to the overall environmental impacts. Besides impacts arising from geopolitical conditions, our study revealed that abiotic augmentation and P. acidilactici bioaugmentation demonstrated superior environmental performance compared to other methods. The results also highlight the importance of international collaboration to implement circular economy approaches in developing countries and accelerating global environmental mitigation efforts. To comprehensively evaluate the environmental sustainability of circular bioeconomy, it is recommended to examine scenarios aligned with socio-economic pathways and various representative concentration pathways.

A personal glucose meter-utilized strategy for portable and label-free detection of hydrogen peroxide

Rapid and precise detection of hydrogen peroxide (H2O2) holds great significance since it is linked to numerous physiological and inorganic catalytic processes. We herein developed a label-free and washing-free strategy to detect H2O2 by employing a hand-held personal glucose meter (PGM) as a signal readout device. By focusing on the fact that the reduced redox mediator ([Fe(CN)6]4-) itself is responsible for the final PGM signal, we developed a new PGM-based strategy to detect H2O2 by utilizing the target H2O2-mediated oxidation of [Fe(CN)6]4- to [Fe(CN)6]3- in the presence of horseradish peroxidase (HRP) and monitoring the reduced PGM signal in response to the target amount. Based on this straightforward and facile design principle, H2O2 was successfully determined down to 3.63 μM with high specificity against various non-target molecules. We further demonstrated that this strategy could be expanded to identify another model target choline by detecting H2O2 produced through its oxidation promoted by choline oxidase. Moreover, we verified its practical applicability by reliably determining extracellular H2O2 released from the breast cancer cell line, MDA-MB-231. This work could evolve into versatile PGM-based platform technology to identify various non-glucose target molecules by employing their corresponding oxidase enzymes, greatly advancing the portable biosensing technologies.

Dietary exposure of the water flea Daphnia galeata to microcystin-LR

ABSTRACT Harmful substances like the cyanotoxin microcystin-leucine-arginine (MC-LR) are commonly found in eutrophic freshwater environments, posing risks to aquatic organisms. The water flea, Daphnia, is a well-established model organism for environmental toxicology research. Nevertheless, there is currently insufficient research on the genes that respond to MC-LR in Daphnia galeata. This study aimed to gain insights into the notable genes that react significantly to MC-LR. In this study, we generated an extensive RNA-Seq sequences isolated from the D. galeata HK strain, Han River in Korea. This strain was nourished with a diet of the green microalga Chlorella vulgaris and treated with pure MC-LR at a concentration of 36 ug/L. The transcriptome profile in response to the MC-LR treatment was obtained and 336 differentially expressed genes were subjected to Gene Ontology (GO) and euKaryotic Orthologous Groups of proteins analyses. GO enrichment analysis showed that chemical stimulus, amino sugar metabolic and catabolic process, oxidative stress, and detoxification were highly enriched, in reverse, proteolysis and fucosylation were underpresented. Detoxification process related genes such as peroxidase-like, chorion, and thyroid peroxidase-like were enriched for eliminating or neutralizing MC_LR from an organism's body. Furthermore, functional protein classification revealed an upregulation of lipid and inorganic ion transport processes, while amino acid and carbohydrate transport processes were found to be downregulated. These findings offer insights into how organisms respond to ecotoxic stimuli, providing valuable information for understanding adaptation or defense pathways.

The Importance of Local Thermal Circulations in PM2.5 Formation in a River Valley: A Case Study From the Lower Yangtze River, China

AbstractPoor air quality is often experienced in densely populated areas located alongside large rivers. The presence of a river valley can modify local meteorology, potentially interfering with the formation of air pollutants such as PM2.5. However, the mechanisms behind PM2.5 formation in river valleys and its impacts on surrounding regions remain poorly understood. This study investigates the formation mechanisms of PM2.5 in the Nanjing reach of the Yangtze River, considering its complex terrain and anthropogenic emissions, through numerical simulation. Simulated results revealed higher PM2.5 concentrations along the Yangtze River compared to the average concentrations in Nanjing, primarily driven by elevated nitrate level. Factors such as higher humidity, wind speed, ageostrophic wind field, and shallow boundary layer were identified as key contributors to the increased PM2.5 concentrations along the river. Our study demonstrates significant impact of local thermal circulations on PM2.5 formation, resulting from the interaction between the large water body of the Yangtze River and the urban area. This phenomenon was confirmed through sensitivity experiments, which showed attenuated local thermal circulations in the absence of the Yangtze River. Source apportionment and process analysis results confirm the dominant roles of local thermal circulation related horizontal and vertical advections, with diurnal fluctuations, in shaping PM2.5 variations along the river. Inorganic chemistry processes also played a non‐negligible role, particularly during polluted conditions. Local thermal circulations in river valleys are crucial for PM2.5 formation, highlighting the need for comprehensive strategies to tackle air pollution in similar regions.

Further study on the genesis of lamellar calcite veins in lacustrine black shale—A case study of Paleogene in Dongying Depression, China

Lamellar calcite veins are prevalent in carbonate-rich, lacustrine dark shale. The formation mechanisms of these veins have been extensively debated, focusing on factors such as timing, depth, material source, and driving forces. This paper examines dark lacustrine shale lamellar calcite veins in the Paleogene strata of Dongying Depression, using various analytical techniques: petrography, isotope geochemistry, cathodoluminescence, inclusion thermometry, and electron probe micro-analysis. Two distinct types of calcite veins have been identified: granular calcite veins and sparry calcite veins. These two types differ significantly in color, grain structure, morphology, and inclusions. Through further investigation, it was observed that vein generation occurred from the shallow burial period to the maturation of organic matter, with a transition from granular calcite veins to sparry calcite veins. The granular calcite veins exhibit characteristics associated with the shallow burial period, including plastically deformed laminae and veins, the development of strawberry pyrite, the absence of oil and gas, weak fractionation in oxygen isotopes, and their contact relationship with sparry calcite veins. These granular calcite veins were likely influenced by the reduction of sulfate bacteria. On the other hand, sparry calcite veins with fibrous grains are antitaxial and closely linked to the evolution and maturation of organic matter. They contain oil and gas inclusions and show a distribution range of homogenization temperature between 90 °C and 120 °C and strong fractionation in oxygen isotopes, indicating formation during the hydrocarbon expulsion period. The carbon isotope analysis of the surrounding rocks and veins suggests that the material for vein formation originates from the shale itself, specifically authigenic micritic calcite modified by the action of methanogens. The opening of horizontal fractures and vein formation is likely driven by fluid overpressure resulting from undercompaction and hydrocarbon expulsion. Veins may form rapidly or through multi-stage composite processes. Early veins are predominantly formed in situ, while late veins are a result of continuous fluid migration and convergence. Furthermore, the veins continue to undergo modification even after formation. This study emphasizes that the formation of lamellar calcite veins in shale is a complex diagenetic process influenced by multiple factors: biology, organic matter, and inorganic processes, all operating at various stages throughout the shale's diagenetic history.

Application of algae in wastewater treatment

Nowadays, water contamination has become one of the most significant environmental issues. The creation and use of algal biotechnology with less investment, good effect and low operating cost has garnered a lot of attention. With the ongoing development of numerous new water treatment technologies, low-cost and effective ecological governance systems have been created quickly. Its purpose is to improve the sewage purification process by improving the inorganic process of organic matter, accelerating the expansion and multiplication of microorganisms, enhancing the metabolic function of microorganisms, and promoting the proliferation of microorganisms. In this article, the removal of nitrogen, phosphorus, heavy metals, antibiotics, pathogens and pesticides by algae was introduced. Additionally, typical algae systems including immobilized algae systems, algal-bacterial symbiotic systems and combination high-rate algae pond systems used in sewage treatment and the limitations and prospects of algae technology were discussed. Algal wastewater treatment is more effective in removing nitrogen and phosphorus than conventional activated sludge processes. Aquaculture wastewater, industrial drainage, municipal sewage, and other distinct forms of water treatment processes can all benefit from the simultaneous transformation and removal of nitrogen, phosphorus, sulfur, refractory organic matter, and heavy metals in sewage that is made possible by algae technology. Engineering techniques and technological advancement will be used to create high-efficiency microalgae wastewater treatment reactors, optimize conditions, increase the utilization efficiency of microalgae biological resources, and apply microalgae to wastewater treatment, which will have a significant impact on water quality and economy.

Diurnal source apportionment of organic and inorganic atmospheric particulate matter at a high-altitude mountain site under summer conditions (Sierra Nevada; Spain)

High-altitude mountain areas are sentinel ecosystems for global environmental changes such as anthropogenic pollution. In this study, we report a source apportionment of particulate material with an aerodynamic diameter smaller than 10 μm (PM10) in a high-altitude site in southern Europe (Sierra Nevada Station; SNS (2500 m a.s.l.)) during summer 2021. The emission sources and atmospheric secondary processes that determine the composition of aerosol particles in Sierra Nevada National Park (Spain) are identified from the concentrations of organic carbon (OC), elemental carbon (EC), 12 major inorganic compounds, 18 trace elements and 44 organic molecular tracer compounds in PM10 filter samples collected during day- and nighttime. The multivariate analysis of the joint dataset resolved five main PM10 sources: 1) Saharan dust, 2) advection from the urbanized valley, 3) local combustion, 4) smoke from a fire-event, and 5) aerosol from regional recirculation with high contribution of particles from secondary inorganic and organic aerosol formation processes. PM sources were clearly associated with synoptic meteorological conditions, and day- and nighttime circulation patterns typical of mountainous areas. Although a local pollution source was identified, the contribution of this source to PM10, OC and EC was small. Our results evidence the strong influence of middle- and long-range transport of aerosols, mainly from anthropogenic origin, on the aerosol chemical composition at this remote site.

The potential role of biofilms in promoting fouling formation in radioactive discharge pipelines

Nuclear facility discharge pipelines accumulate inorganic and microbial fouling and radioactive contamination, however, research investigating the mechanisms that lead to their accumulation is limited. Using the Sellafield discharge pipeline as a model system, this study utilised modified Robbins devices to investigate the potential interplay between inorganic and biological processes in supporting fouling formation and radionuclide uptake. Initial experiments showed polyelectrolytes (present in pipeline effluents), had minimal effects on fouling formation. Biofilms were, however, found to be the key component promoting fouling, leading to increased uptake of inorganic particulates and metal contaminants (Cs, Sr, Co, Eu and Ru) compared to a non-biofilm control system. Biologically-mediated uptake mechanisms were implicated in Co and Ru accumulation, with a potential bioreduced Ru species identified on the biofilm system. This research emphasised the key role of biofilms in promoting fouling in discharge pipelines, advocating for the use of biocide treatments methods.

Does the merger improve the operating performance of the company? Evidence from the beverage industry in India.

Background: There is fierce market competition both locally and globally. Every organisation seeks to maintain itself and, more crucially, to develop quickly through inorganic means. The expansion of a company through mergers and acquisitions is an inorganic process. Organic growth takes a very long period and is time-bound, but inorganic growth through mergers may be achieved quickly. This research aimed to determine whether the operating results of Indian beverage firms have improved after the merger or not. Methods: In order to assess merger-related advantages to the acquiring firms, this study used the operating performance technique, which contrasts the pre-merger and post-merger performance of corporations using accounting data. Secondary data were used to carry out this study. The operating performance was assessed on six operating parameters (ratios) i.e. Operating Profit Margin, Gross and Net Profit Margin, Debt-Equity, Return on Net Worth and Capital Employed. The comparison was done for three years pre and post-merger period of these operating ratios. Results: The findings demonstrate that mergers do not seek to increase owner wealth. This finding shows that rather than just becoming larger and achieving covert goals, managers should pay more attention to post-merger integration challenges in order to produce merger-induced synergies. Conclusion: This study shows that the M&As have not had a good effect on a company's operating performance, especially for the chosen beverage companies in India. Since financial measures cannot fully account for the influence of mergers on business performance, future research may create other metrics for merger-related gains. Research that provides profound insights into the causes and trends of post-merger business performance through the different types of mergers and industries would also be beneficial.

Untimely Ecology: A Genealogy of Biosphere to Rethink Temporality in the Anthropocene

One of the critical challenges of our contemporary world is rethinking temporality to face the global catastrophe of the Anthropocene. Recent theories in social sciences and philosophy envision a new conceptualization of our biosphere in which human and non-human life forms, inert objects, and technological devices are entangled. However, these approaches present two major problems: a) they affirm that organic and inorganic processes are ontologically symmetrical and have the same type of agency; and b) they consider that technicity on planet Earth emerges in the hominization process. In this work, we will develop a genealogy of our biosphere that proposes an ecological and untimely alternative: life, from its earliest beginning, is a technical phenomenon that changes the face of the universe.

Co-occurrence patterns in biofloc microbial communities revealed by network analysis and their impact on the host

The complex aggregation of bacteria flocs (bioflocs) plays a vital role in the inorganic nitrogen transformation process within biofloc systems. However, few reports have focused on the bacterial co-occurrence of flocs supplemented with different carbohydrate sources. In this study, a correlation-based microecological network analysis method was applied to reveal the bacterial interactions of flocs under three different aquaculture systems: a clear water system (CON group), a biofloc system using glucose (GLU) as a carbon source, and a biofloc system using starch (STA) as a carbon source. The results showed that (i) the GLU group exhibited higher nitrogen removal efficiency and a higher DOC/total inorganic nitrogen ratio (68.80 ± 9.18% and 19.19 ± 6.78, respectively) than the STA group (55.59 ± 16.26% and 15.30 ± 11.08, respectively). The bacterial co-occurrence patterns in the three systems were not random, with each carbohydrate corresponding to a unique bacterial community niche. (ii) Firmicutes was the core phylum in the biofloc technology (BFT) system, while Bacillus, Carnobacterium, and Staphylococcus were the core genera that ensured the stability of nitrogen removal in the system based on network analysis results. (iii) In the GLU group, the abundance of Firmicutes was increased and corresponded to a higher Firmicutes/Bacteroidetes (F/B) ratio in the fish gut, which promoted host in situ growth performance. Application of the ecological concepts in this study could lead to the identification of core/satellite genera in bioflocs and promote scientific hypotheses toward more in-depth metabolic and functional research on biofloc systems.

The geochemical processes affecting the mobility of Cu, Pb, Zn during phytostabilization on sulfidic mine tailings revealed by a greenhouse study

Sulfidic mine tailings have the potential to release toxic metals into the surrounding environment. Phytostabilization can stabilize these toxic metals in the rhizosphere, providing a sustainable method for mine reclamation. However, previous research has not examined the inorganic geochemical processes in the rhizosphere that are significant for controlling acid mine drainage. Therefore, a greenhouse study was conducted to explore the geochemical processes affecting the mobility of Cu, Pb, and Zn through the establishment of phytostabilization on sulfidic mine tailings. The mineralogy of substrates before and after experiments and the changes in metal concentrations and pH of the drainage were analyzed. The results showed that at the end of the experiments, pH of pot substrates with plants became acidic (pH ranging from 2.59 to 3.77), the concentrations of Cu, Pb, and Zn in the drainage increased (up to 20.14 mg/L of Cu, 2.28 mg/L of Pb, and 3199.87 mg/L of Zn), leading to the generation of acid mine drainage. It was concluded that, in addition to the sulfide oxidation, two other acidification processes played a role: the decomposition of organic matter and the release of roots exudates, in decreasing pH and increasing metal concentrations in the drainage from amended tailings. The acidity in the rhizosphere was neutralized sequentially through the following geochemical processes: (1) dissolution of carbonates, (2) dissolution of Al&Fe (oxy)hydroxide, and (3) silicates weathering. The long-term reliability of phytostabilization can be achieved by re-applying amendments to initiate these neutralization processes. This research has filled the research gap regarding the geochemical mechanisms controlling the migration of metals in the rhizosphere during phytostabilization with two grass species (Pascopyrum and Lolium multiflorum). It provides a valuable reference for designers and engineers when considering metal immobilization in sulfidic mine tailings through the technique of phytostabilization during mine reclamation and closure stage.

Construction of g-C3N4-based photo-enzyme-coupled catalytic system and application in the efficient degradation of acridine

Acridine, as a nitrogen heterocyclic pollutant, poses a huge ecological and human health hazard, and its efficient degradation is one of the top tasks. A novel photo-enzyme-coupled catalytic system was constructed by coupling horseradish peroxidase (HRP) with graphite carbon nitride (g-C3N4) through a simple inorganic hybridization process. The obtained g-C3N4/HRP nanoflowers not only increase the enzyme loading capacity and enzyme activity, but also promote the efficient separation of carriers. More importantly, the H2O2 generated by g-C3N4 directly participates in the redox cycle reaction of HRP, inducing photo-enzyme synergistic catalysis. Therefore, compared to HRP nanoflowers and g-C3N4 nanoflowers, g-C3N4/HRP nanoflowers exhibited higher catalytic efficiency for the degradation of acridine. Thus, the photo-enzyme coupled catalyst proposed in this study provides a promising platform for the degradation of acridine pollutants by combining enzymes with photocatalysts through inorganic hybridization.