Degradation Effects Research Articles

Effects of vegetation degradation on soil microbial communities and ecosystem multifunctionality in a karst region, southwest China

Vegetation degradation caused by intense human disturbances poses a significant challenge to the preservation and improvement of ecosystem functions and services in the karst region of southwest China. Soil microorganisms are major regulators of ecosystem multifunctionality (EMF). Currently, there is a dearth of knowledge regarding the effects of vegetation degradation on soil microbial communities and their corresponding multiple ecosystem functions in karst regions. In this study, we selected the vegetation degradation sequences of second natural forest (NF), agroforestry (AS) and cropland (CL) to investigate the diversity of bacterial, fungal and protistan communities, and their hierarchical co-occurrence network, and EMF to explore the relationships between them. Compared to the NF, the carbon cycling index, nitrogen cycling index, soil water regulation power, and the EMF were significantly decreased by 8.2%–50.6%, 48.7%–86.8%, 19.8%–24.5%, and 31.4%–69.5% in the AS and CL, respectively. The development of EMF can be explained by the fungal, protistan and microbial hierarchical β-diversity, as well as the complexity (e.g. degree) of microbial hierarchical interactions during the process of vegetation degradation. Notably, correlations between the abundances of sensitive amplicon sequence variants (sASVs) for different karst vegetation types and EMF varied in distinct network modules, being positive in module 1 and negative in module 2. Moreover, the relative abundance of keystone taxa in fungal and protistan communities provided greater contributions to EMF than the bacterial communities. Additionally, random forest modeling showed that carbon and nitrogen sources, and soil water content, and trace elements (e.g. exchangeable magnesium, iron, manganese, and zinc) were identified as key driving factors of the EMF. Collectively, our findings demonstrate that vegetation degradation obviously alters soil microbial diversities and hierarchical interactions, emphasizing their key role in maintaining ecosystem functions and health in karst regions.

Spatiotemporal assessment of deforestation and forest degradation indicates spillover effects from mining activities and related biodiversity offsets in Madagascar

Mining has severe environmental and social impacts. To compensate for the environmental damage caused at mining sites, mining companies are required to engage in biodiversity offsetting activities elsewhere. In forest landscapes, most offsetting policies focus on compensating for biodiversity loss from deforestation, while forest degradation is largely ignored – even though it contributes substantially to biodiversity loss. One reason for this is that forest degradation is challenging to assess and monitor. This study focuses on a large nickel and cobalt mine in Madagascar. By analysing remote sensing time series, we assess detailed annual forest change dynamics and distinguish different types of forest disturbance within and around the mining lease area and the two main associated biodiversity offset areas between 2006 and 2020. Our results show that deforestation rates within the two biodiversity offset areas are low (18 ha, or 0.4%; 164 ha, or 2.4%), suggesting that conservation measures are effective. However, this is not the case when looking at forest degradation. We found that substantial shares of forest within the two biodiversity offset areas are affected by degradation (545 ha, or 11.4%; 662 ha, or 9.7%). In the surrounding unprotected landscape, the rates of deforestation (451 ha, or 6.7%; 553 ha, or 4.9%) and forest degradation (2360 ha, or 34.8%; 5794 ha, or 51.1%) are much higher. The spatiotemporal pattern indicates spillover effects for both deforestation and forest degradation. Taken together, our findings show that restrictions on local communities’ access to forest resources within biodiversity offset areas affect the surrounding landscape and can cause substantial additional adverse environmental impacts there. We also demonstrate that forest degradation monitoring is feasible, and that forest degradation is widespread even though it is still largely ignored. These findings should be considered in future biodiversity offsetting policies and best practices.

Synergistic effect of Sonophotocatalytic degradation of crystal violet and alizarin red S dyes using Ag-doped ZnSnO3 nanoparticles

This study proposes an environmentally conventional sonophotocatalytic method that uses silver (Ag)-doped ZnSnO3 nanoparticles (NPs) to effectively eliminate industrial dye-polluted wastewater. This study was conducted to investigate the effect of the Ag doping ratio of the synthesized ZnSnO3 NPs on the removal of dye molecules. We used crystal violet (CV) and alizarin red S (AR) dyes as test pollutants to examine the catalytic activity of the synthesized Ag-doped ZnSnO3 NPs in response to the ultrasound and visible light stimulation. The most effective photocatalytic performance was exhibited by 4 % Ag-ZnSnO3 NPs, which degraded 95 % of the CV and 52 % of the AR dye in 100 min. Surprisingly, using sonophotodegradation to combine ultrasound with visible-light irradiation has resulted in almost complete degradation of the CV dye in 100 min, demonstrating a strong beneficial synergy between the sonocatalytic and photocatalytic processes. Additionally, the sonophotocatalytic degradation of the CV and AR dyes was examined at various pH values. It shows to have high stability across several cycles of dye treatment, indicating that this method can be used for industrial effluents. Scavenger tests demonstrated that the primary active species in the dye degradation is O2•−. Ultimately, the prepared Ag-ZnSnO3 NPs and sonophotocatalytic processes may offer a promising path toward a variety of environmental uses, including the remediation of water and the removal of other organic contaminants.

A method of degradation mechanism-based unsupervised remote sensing image super-resolution

Remote sensing image (RSI) super-resolution (SR) is an efficient and low-cost technique to achieve high-resolution and high-quality reconstruction images. The quality of RSI SR reconstruction is affected by the prior information contained in the degradation model. Therefore, studying how to incorporate more RSI degradation prior into the degradation model is crucial. This article presents an approach to design the degradation model by extracting degradation factors from the perspective of remote sensing imaging mechanisms. It includes two aspects: simulating the atmospheric scattering effect through RGB channel weights downsampling and the comprehensive degradation effect of the remote sensing imaging platform through combined blurring. Furthermore, we proposed a high-performance RSI SR network based on degradation mechanism (RSN-DM), which includes a degrader D and a generator G, to employ remote sensing prior fully. We conducted experiments on the UC Merced Land-Use and WPU-RESIS45 datasets, demonstrating that our proposed method is effective. Our method achieves state-of-the-art (SOTA) performance in quantitative evaluation and visual quality. Finally, we apply the proposed degradation model to other networks to further validate the model's effectiveness. Therefore, the degradation model proposed in this paper can enhance the performance of remote sensing image super-resolution techniques in practical applications.

Rapid and scalable detection of synthetic mRNA byproducts using polynucleotide phosphorylase and polythymidine oligonucleotides

ABSTRACT Production and storage of synthetic mRNA can introduce a variety of byproducts which reduce the overall integrity and functionality of mRNA vaccines and therapeutics. mRNA integrity is therefore designated as a critical quality attribute which must be evaluated with state-of-the-art analytical methods before clinical use. The current study first demonstrates the effect of heat degradation on transcript translatability and then describes a novel enzymatic approach to assess the integrity of conventional mRNA and long self-amplifying mRNA. By first hybridizing oligo-T to the poly(A) tail of intact mRNA and subsequently digesting the unhybridized RNA fragments with a 3’-5’ exoribonuclease, individual nucleotides can be selectively released from RNA fragments. The adenosine-based fraction of these nucleotides can then be converted into ATP and detected by luminescence as a sensitive indicator of mRNA byproducts. We developed a polynucleotide phosphorylase (PNPase)-based assay that offers fast and sensitive evaluation of mRNA integrity, regardless of its length, thus presenting a novel and fully scalable alternative to chromatographic-, electrophoresis-, or sequencing-based techniques.

Zero-valent iron-loaded Ti3C2-MXene activated by persulfate for the degradation of tetracycline hydrochloride: Efficiency and mechanism

The unique two-dimensional "sandwich" structure and excellent surface chemistry of Ti3C2-MXene show great potential for environmental treatment. In this paper, a novel degradant, Ti3C2-MXene was modified by zero-valent iron (Fe0) composites (Fe0/Ti3C2-MXene) were prepared, which could successfully degrade tetracycline hydrochloride (TC) under sodium persulfate (PDS) conditions. Characterization methods such as SEM, XRD, and XPS demonstrated that Fe0/Ti3C2-MXene still retained the two-dimensional layered structure of Ti3C2-MXene, and the Fe0 nanoparticles were successfully attached to the surface and interlayers of Ti3C2-MXene. Meanwhile, the effects of catalyst dosage, PDS dosage, initial concentration, pH, and coexisting anions and cations on the degradation were investigated. The results indicated that the degradation of TC (80 mL, 20 mg/L) by 2 mg of Fe0/Ti3C2-MXene and 10 mg of PDS under 25 °C and pH=4 could reach 80 % within 2 min. There is a synergistic effect of adsorption and oxidative degradation in the degradation of TC by Fe0/Ti3C2-MXene. SO4-• and 1O2 play a major role during TC degradation by the radical quenching experiments, XPS and LC-MS. This work not only provides a new strategy for the modification of Ti3C2-MXene with Fe0, but also offers new insights into the efficient degradation of antibiotics in water by Ti3C2-MXene.

Solvent-controlled assembly of helical coordination polymers based on lactate synthon from two-dimensional layer to three-dimensional framework

Compound (R)-4-(1-carboxyethoxy)-2-methylbenzoic acid ((R)-H2cma) was prepared from (S)-methyl lactate and 4-hydroxy-2-methylbenzoic acid. (R)-H2cma as chiral synthon assembled with 1,3-di(pyridin-4-yl)propane (1,3-dpp) and Ni2+ ions to obtain helical chiral complexes {[Ni2((R)-cma)2(1.3-dpp)2]·H2O}n (HU18-R) and {[Ni2((R)-cma)2(1.3-dpp)2(H2O)]·3H2O}n (HU19-R) in different solvent systems. Single crystal tests revealed that HU18-R is a two-dimensional (2D) structure with two independent Ni2+ centers and HU19-R is a three-dimensional (3D) framework containing dinuclear [Ni2(CO2)2(H2O)]2+ clusters. Four types of helices were formed in HU18-R and HU19-R by chiral transfer or induction. In HU18-R, small right-handed (R)-cma-Ni chain and large right-handed (R)-cma-Ni-1.3-dpp chain were constructed by chiral transfer. For HU19-R, helical nano-channel based on achiral 1.3-dpp ligands and Ni2+ ions was obtained from chiral induction method and small (R)-cma-Ni chain was built from chiral transfer. As semi-conducting materials, HU18-R and HU19-R indicate strong absorption capacity for UV–vis light and low-impedance properties. Under UV light, they have noticeable catalytic effects for degradation of methylene blue (MB). Moreover, magnetic tests confirmed that HU18-R and HU19-R have ferromagnetic and antiferromagnetic properties, respectively.

Assessing the Potential of Aconitum Laeve Extract for Biogenic Silver and Gold Nanoparticle Synthesis and Their Biological and Catalytic Applications.

The adoption of green chemistry protocols in nanoparticle (NP) synthesis has exhibited substantial potential and is presently a central focus in research for generating versatile NPs applicable across a broad spectrum of applications. In this scientific contribution, we, for the first time, examined the ability of Aconitum Laeve (A. Laeve) crude extract to synthesize silver and gold nanoparticles (AgNPs@AL; AuNP@AL) and explored their potential applications in biological activities and the catalytic degradation of environmental pollutants. The synthesized NPs exhibited a distinctive surface plasmon resonance pattern, a spherical morphology with approximate sizes of 5-10 nm (TEM imaging), a crystalline architecture (XRD analysis), and potential functional groups identified by FTIR spectroscopy. The antibacterial activity was demonstrated by inhibition zones that measured 16 and 14 mm for the AgNPs@AL and AuNP@AL at a concentration of 80 µg/mL against Staphylococcus aureus and 14 and 12 mm against Escherichia coli, respectively. The antioxidant potential of the synthesized NPs was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2-Phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-Oxide (PTIO), and 3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assays. Our findings suggest that the AuNP@AL effectively countered the tested radicals considerably, displaying IC50 values of 115.9, 103.54, and 180.85 µg/mL against DPPH, PTIO, and ABTS, respectively. In contrast, the AgNPs@AL showed IC50 values of 144.9, 116.36, and 95.39 µg/mL against the respective radicals. In addition, both the NPs presented significant effectiveness in the photocatalytic degradation of methylene blue and rhodamine B. The overall observations indicate that A. Laeve possesses a robust capability to synthesize spherical nanoparticles, exhibiting excellent dispersion and showcasing potential applications in both biological activities and environmental remediation.

Innovative Treatment of Ancient Architectural Wood Using Polyvinyl Alcohol and Methyltrimethoxysilane for Improved Waterproofing, Dimensional Stability, and Self-Cleaning Properties

This study introduced a novel two-step treatment to enhance the waterproofing, dimensional stability, and self-cleaning capabilities of ancient architectural wood. The process was initiated with the immersion of wood in an organic hybrid sol, composed of an acidic methyltrimethoxysilane (MTMS)-based silica sol and polyvinyl alcohol (PVA), which effectively sealed the wood’s inherent pores and cracks to mitigate degradation effects caused by aging, fungi, and insects. Subsequently, the treated wood surface was modified with an alkaline MTMS-based silica sol to form a functional superhydrophobic protective layer. The modification effectiveness was meticulously analyzed using advanced characterization techniques, including scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The results demonstrated substantial improvements: the modified wood’s water contact angle (WCA) reached 156.0°, and the sliding angle (SA) was 6.0°. Additionally, the modified wood showed a notable reduction in water uptake and moisture absorption, enhancing its dimensional stability. The superhydrophobic surface endowed the wood with excellent self-cleaning properties and robust resistance to pollution. Enhanced mechanical durability of superhydrophobic surface was observed under rigorous testing conditions, including sandpaper abrasion and tape peeling. Furthermore, the modification improved the thermal stability, compressive strength, and storage modulus of the wood. Collectively, these enhancements render this modification a potent methodology for the preservation and functional augmentation of historic architectural woodwork.

Smart indoor gardening: elevating growth, health, and automation

Recently, indoor systems for growing plants have emerged as a promising approach to address the problems related to extreme weather conditions outdoors. However, such systems must manage the plants surrounding environments to satisfy the environmental and the economical requirements. In this line, any proposed solution must address challenging factors such as plants diseases and unordinary climate situations. In this paper, propose an internet of things (IoT) indoor system that can be used to facilitate the plant growing process. The proposed system is designed to provide alternatives for outdoor climate dependency such as the vitamins provided through sunlight. Moreover, renewable energy sources (sunlight) are employed to reduce the impact on the environment. With the help of several types of sensors, the system continuously monitors the plants through their growing journey. Whereas actuator devices are employed to control the plant-feeding process based on the sensors’ reported values. All the collected data will be uploaded to the cloud for analysis, utilizing a website. Additionally, the architecture of the provided system eliminates the need for human involvement, which has a degrading effect on the plant growing process.

Improvements to a novel learning algorithm for model-based wind turbine controllers

Wind turbine controllers are nowadays ever more advanced and rely on accurate internal controller model information. Therefore a calibrated model is needed for attaining predictable controller performance and ensuring stable operation. To calibrate the internal model information, a novel learning control scheme has recently been proposed that exploits the dynamics of the closed-loop controlled wind turbine system, without the need for wind speed measurements. The learning algorithm thereby periodically excites the generator power controller input signal. An extremum-seeking demodulation scheme was used to calibrate the internal model information. This paper improves the existing learning scheme in two ways: Firstly, it investigates how the frequency of the excitation signal influences the signal-to-noise ratio. Secondly, the problem was reformulated as a root-finding problem. This requires using the in-phase component of the phase-corrected learning signal. In addition, a precalculated lookup table relates the measured in-phase component directly to model uncertainty. It was found that an increased excitation frequency improves the signal-to-noise ratio (SNR) by an order of magnitude. Combined, these contributions improve the convergence speed more than twenty times, addressing the effect of aerodynamic degradation and its consequences on controller performance.

English

Soil degradation is a global problem. Over the last several decades, the effects of land degradation in Tunisia are starting to have increasingly serious socio-economic and environmental repercussions. The agricultural sector is most seriously affected. The Tunisian Sahel, despite its modest topographical conditions, has not escaped this threat, especially upstream of the El Maasra Wadi. The fertile soils and homogeneous topography of this area, which dates to Roman times, are highly favorable to a wide range of agricultural practices. The Central Sahel has a long history of olive-growing, followed by a shift to irrigated farming in the 1970s. Today, it is given a multifunctional and multidimensional importance due to the complexity of conflicts of interest between different users. Rural abandonment, mining activity and pastoral pressure have all been behind the soil crisis, which is still largely unknown in detail in terms of the processes involved, the mechanisms behind them and the pace at which they are occurring. Today, there is an urgent need for tools and reliable methods to diagnose the state of soils, to elucidate the various facets of erosive processes and create the structural conditions necessary for their preservation. In the same vein, this research project was initiated in the Wadi El Maasra watershed to quantify soil losses using two methods: empirical model (USLE equation) and experimental based on the isotopic tracer of the Caesium-137. The two methods showed an almost identical geographical distribution, but slightly different loss rates. The specific soil loss obtained from the USLE model was of the order of 15 t ha-1 year-1, which appears to be largely underestimated compared with the loss rate obtained by the Caesium-137 method, which was of the order of 32 t ha-1 year-1.

The Effect of Polycaprolactone Polymer Degradation in Compost on Seed Germination

Abstract Polycaprolactone (PCL) is a biodegradable synthetic polymer derived from petroleum that can be broken down by microorganisms. Due to its low melting point, it is suitable for composting. PCL has various applications, including in medicine and agriculture. This study investigates whether PCL degradation in compost affects seed germination. The study tested the effect of PCL extracts from compost with different temperatures and concentrations on the germination of seeds from four edible plant species: cress, lettuce, mustard, and rocket. The results showed that at low temperatures and low PCL concentrations, there was no effect on seed germination. However, at higher temperatures (55°C) and higher PCL concentrations (10% and 5%), there was a signiIicant negative effect on seed germination, with no germination in 10% PCL treatments and only 53.3% germination in 5% PCL treatments. This inhibition was observed across all plant species. The study concludes that high temperatures and high PCL concentrations in compost can negatively impact seed germination.

Performance and mechanism of constructed CuO/CeO2 p–n heterojunction for photocatalytic degradation of methylene blue

CuO/CeO2 p–n heterojunction composites were synthesized using an easy microwave reflux method with homogeneous precipitation technology, and their photocatalytic performance in terms of methylene blue degradation was studied. The results showed that the degradation effect of the CuO/CeO2 heterojunction composites was substantially stronger than that of CeO2. The composite prepared with a Cu/Ce molar ratio of 1/3 (1/3 Cu/Ce) exhibited the highest catalytic activity, achieving a degradation efficiency of 96.2% within 180 min. The improved photocatalytic performance was attributed to the formation of a p–n heterojunction between CuO and CeO2, which considerably promoted the separation and transport of photogenerated carriers. The band offset of the CuO/CeO2 heterostructure was calculated; its valence band offset was 1.58 eV and conduction band offset was −0.48 eV, further demonstrating the formation of a p–n heterojunction.

Safety evaluation of offshore oil and gas well string based on corrosion rate prediction

The combined effects of corrosion, temperature, and pressure can cause safety issues such as shortened lifespan and failure of offshore high temperature and high pressure oil and gas well strings. This paper focuses on a certain sea area and conducts experiments on CO2 corrosion of different string materials under different temperature and partial pressure conditions. Combined with the two-phase flow wellbore temperature and pressure-coupling model, a corrosion rate prediction model based on Back Propagation Neural Network optimized by Genetic Algorithm (GA-BPNN) is established for predicting corrosion rate along the wellbore depth. At the same time, based on the API 5C3 standard, considering the degradation effect of thermally induced metal string strength and the influence of environmental pressure, a safety evaluation model of offshore oil and gas well string based on corrosion rate prediction was established, and analysis of the change law of residual strength of the string and prediction of remaining life under the influence of different factors were carried out.

Degradation of tetracycline by combining hydrodynamic cavitation (HC) and ultraviolet (UV)

Abstract Antibiotics have become a new type of organic pollutant. Traditional methods of antibiotic treatment have several problems, including low treatment efficiency, high cost, and low safety. As an emerging process intensification technology, hydrodynamic cavitation (HC) can significantly enhance degradation efficiency coupling with other treatment means. This work studies the degradation effect of a representative antibiotic, tetracycline, by combining HC and UV. The effect of various operating factors, including inlet pressure, initial concentration, pH, and temperature, is analyzed. It is found that HC/UV can obtain 1.7∼4.2 times more effectiveness than that of sole use of HC or UV.

Biochar supported Pseudomonas putida based globules for effective removal of Bisphenol A with a practical approach

The widespread and inevitable use of plastic has led to prospective ecological problems through Bisphenol A (BPA), a synthetic chemical in plastic manufacturing. The present study addresses a unique methodology for eliminating BPA using the assistance of Pseudomonas putida. In the present work, biomass was torrefied to generate biochar with highly porous networks that could accommodate the bacterial species for effective colonization and multiplication. The designed biochar-bacterial globules demonstrated the ability to effectively remove BPA (96.88%) at a concentration of up to 2 g/L. The biochar-bacterial globules could effectively adsorb BPA at a low concentration of 20 mg/L. The alteration in pH did not impact the globule's performance, providing additional support for the practical utilization of these globules in polluted water bodies. In addition, the biochar-bacterial globules exhibited superior effectiveness in degradation compared to the standard levels, particularly in saline conditions. The simplicity and effectiveness of the approach make it promising for real-world implementation in addressing ecological problems associated with BPA contamination.

Water Intrusion: An Analysis of Water Sources, Categories, and the Degradation Science of Building Materials

Water intrusion into a building envelope describes the unwanted movement of water or vapor into a building, where it causes damage. Various factors dictate water intrusion category determination and classification. These factors include, but are not limited to, the type and degree of water intrusion, the source and route of the contamination, and exposure time, as well as geographical environmental conditions. This comprehensive research paper looked at the literature and the science to explore the bases for indoor environmental professional (IEP) classification and category determination, but also the science behind the effects of water intrusion on building materials (BM). The efficacy of building materials once degradation has occurred and any accelerating effects impacting the efficiency of building materials and their loss of integrity were closely examined in terms of material microstructural and compositional changes. The damaging effects of moisture and heat on building materials are called hygrothermal damage, which compromises the properties and use of materials. Both aspects of building integrity, i.e., water intrusion and structural deterioration, should be of concern when mitigating and remediating the intrusion of moisture. Previous research on the clarification of water categories for water intrusions is lacking. Past approaches to water classification have lacked universal scientific clarity and understanding. In addition to a need to understand the effects that water category might have on building materials and their corresponding degree of degradation, more science and reviews are needed. The need for proper class and category determination for the remediation of water intrusion within buildings is the first step toward achieving correct mitigation to ensure human health and safety. The possible adverse health effects of water intrusion need focus and cohesion for the determination of categories. We know that the final determination of water categories differs according to the degree of contamination over time and the degree of a given class of water intrusion; however, what role do the route and initial water contamination play in the determination of the category? The following paper aims to provide not only a review of the science but also an elaboration of the category determination process and the degradation effects on building materials which should be considered, as well as possible avenues of scientific research.

Regional differences in lead (Pb) and tetracycline (TC) binding behavior of sediment dissolved organic matter (SDOM): Effects of DOM heterogeneity and microbial degradation

Lake Nansi, primarily dominated by macrophytes, faces threats from heavy metals and antibiotics due to human activity. This study investigated sediment dissolved organic matter (SDOM) characteristics and complexation of lead (Pb) and tetracycline (TC) in barren zone (BZ) and submerged macrophytes zone (PZ). Additionally, a microbial degradation experiment was conducted to examine its impact on the regional variations in complexation. SDOM abundance and protein-like materials in PZ was significantly greater than in BZ, indicating a probable contribution from the metabolism and decomposition of submerged macrophytes. Both zones exhibited a higher affinity of SDOM for Pb compared to TC, with all four components participating in Pb complexation. Protein-like materials in PZ had a higher binding ability (LogKPb=4.19 ± 1.07, LogKTC=3.89 ± 0.67) than in BZ (LogKPb=3.98 ± 0.61, LogKTC=3.69 ± 0.13), suggesting a potential presence of organically bound Pb and TC due to the higher abundance of protein-like materials in PZ. Although microbial communities differed noticeably, the degradation patterns of SDOM were similar in both zones, affecting the binding ability of SDOM in each. Notably, the fulvic-like component C4 emerged as the dominant binding material for both Pb and TC in both zones. Degradation might increase the amount of organically bound TC due to the increase in the LogKTC.

Biofiltration of toluene and ethyl acetate mixture by a fungal-bacterial biofilter: Performance and community structure analysis

The inhibitory effect of hydrophilic volatile organic compounds (VOCs) on hydrophobic VOCs removal was found to be efficiently reduced by the fungal-bacterial biofilters (F&B-BFs) developed in the present study. Overall, the toluene and ethyl acetate mixture removal efficiencies (REs) and elimination capacities (ECs) of F&B-BFs were superior to those of bacterial biofilters (B-BFs). The REs for toluene and ethyl acetate were 32.5 ± 0.8 % and 74.6 ± 1.0 %, respectively, for F&B-BFs, in comparison to 8.0 ± 0.3 % and 60 ± 1.3 % for B-BFs. The ECs for toluene and ethyl acetate were 13.0 g m−3 h−1 and 149.2 g m−3 h−1, respectively, for the F&B–BF, compared to 3.2 g m−3 h−1 and 119.6 g m−3 h−1 for the B-BFs. This was achieved at a constant empty bed residence time (EBRT) of 45 s. F&B-BFs exhibited a superior mineralization efficiencies (MEs) compared to B-BFs for a VOC mixture of toluene and ethyl acetate (≈36.1 % vs ~ 29.6 %). This is attributed to the direct capture of VOCs by the presence of fungi, increased the contact time between VOCs and VOCs-degrading bacteria, and even distribution of VOCs-degrading bacteria in the F&B-BFs. Moreover, compared with B-BFs, the coupling effect of genus Pseudomonas degradation, and unclassified_f_Herpotrichiellaceae and unclassified_p_Ascomycota adsorption of F&B–BF resulted in a reduction in the impact of the presence of hydrophilic VOCs on the removal of hydrophobic VOCs, thereby enhancing the biofiltration performance of mixtures of hydrophilic and hydrophobic VOCs.