Resource Utilization Strategies Research Articles

Cu1-Fe Dual Sites for Superior Neutral Ammonia Electrosynthesis from Nitrate.

The electrochemical nitrate reduction reaction (NO3RR) is able to convert nitrate (NO3-) into reusable ammonia (NH3), offering a green treatment and resource utilization strategy of nitrate wastewater and ammonia synthesis. The conversion of NO3- to NH3 undergoes water dissociation to generate active hydrogen atoms and nitrogen-containing intermediates hydrogenation tandemly. The two relay processes compete for the same active sites, especially under pH-neutral condition, resulting in the suboptimal efficiency and selectivity in the electrosynthesis of NH3 from NO3-. Herein, we constructed a Cu1-Fe dual-site catalyst by anchoring Cu single atoms on amorphous iron oxide shell of nanoscale zero-valent iron (nZVI) for the electrochemical NO3RR, achieving an impressive NO3- removal efficiency of 94.8% and NH3 selectivity of 99.2% under neutral pH and nitrate concentration of 50 mg L-1 NO3--N conditions, greatly surpassing the performance of nZVI counterpart. This superior performance can be attributed to the synergistic effect of enhanced NO3- adsorption on Fe sites and strengthened water activation on single-atom Cu sites, decreasing the energy barrier for the rate-determining step of *NO-to-*NOH. This work develops a novel strategy of fabricating dual-site catalysts to enhance the electrosynthesis of NH3 from NO3-, and presents an environmentally sustainable approach for neutral nitrate wastewater treatment.

Structural and Successional Dynamics of Old-Growth Mixed Oak Forests in the West Qinling Mountains

Understanding the composition and structure of forest trees is crucial to comprehending the properties and functions of forests. It also helps in implementing effective management strategies for sustainable resource utilization. Our study analyzed the structural dynamics of the old-growth mixed oak forests in the Xiaolongshan Forest region, focusing on three long-term monitoring plots (A, B, C). We examined the tree species composition, diameter distribution, mortality, and recruitment dynamics of different successional species groups, as well as the spatial distribution patterns of living and dead trees, with surveys conducted every five years. The findings indicate: (1) Plot A experienced a decline in stand density and species diversity during the survey period, with the Importance Value Index (IVI) of pioneer successional species continually decreasing in plots B and C. (2) The tree diameter distribution structure in plot A significantly differed from other plots, showing notable change between 2007 and 2012. (3) All plots exhibited lower, well-balanced community-level demographic parameters based on stem number, but a higher recruitment rate for later successional species groups based on basal area. (4) Dead individuals in plot A had a slight clustering distribution, while the other plots showed a random distribution. We conclude that the individual growth rate significantly impacts the dynamics of the natural Quercus aliena var. acuteserrata forest, with pioneer species groups being gradually replaced by early or late-successional species groups in the succession process.

Effects of nitrogen addition and leaf age on needle traits and the relationships among traits in Pinus koraiensis

Leaf functional traits are essential for the growth and adaptation of trees to environmental changes. However, how needle traits and trait–trait relationships respond to different nitrogen (N) addition rates and leaf ages remain unclear for evergreen coniferous species. Our study aimed to investigate the effects of N addition and leaf age on needle traits and their bivariate correlations. Understanding resource utilization and distribution strategies during tree growth under the background of increased N deposition is important. We conducted a six-year manipulative field experiment in a Pinus koraiensis plantation in northeastern China with variable N addition levels: control (no N addition, CK); 20 kg N ha−1yr−1 (low-N, LN); 40 kg N ha−1yr−1 (medium-N, MN); and 80 kg N ha−1yr−1 (high-N, HN). The needle trait data were collected in September. The morphological traits, i.e., specific leaf area (SLA) and leaf dry matter content (LDMC); and chemical traits, i.e., leaf nitrogen concentration (LNC), leaf phosphorus concentration (LPC), and leaf nonstructural carbohydrates (NSC) concentrations, were measured to investigate the changes in needle traits and their bivariate correlations. We found that N addition and needle age significantly affected needle traits, and the effect of needle age was much stronger than that of N addition. N addition and needle age had no significant interaction effects on any of the traits except for the LNC. Due to the dispersal trait values of current-year needles, there were almost no significant bivariate correlations between traits under different N addition rates. The SLA–LDMC and LDMC–LNC relationships were found to differ among the various N addition rates, and other traittrait relationships may be relatively stable because of the weak plasticity of older needles. Additionally, needle age significantly affected the slope of the SLA–LDMC relationship and the elevation of the LDMC–LPC and NSC–LNC relationships, indicating differences in the ecological strategies of needles at different ages. In summary, our findings emphasize that trait–trait relationships in current-year and older needles were inconsistent in response to N addition and that the optimal allocation of resources in needles was based on their functional needs during leaf aging.

Exploring Surface Water-Groundwater Interactions: A Multidisciplinary Approach

Surface water-ground water interaction plays a crucial role in hydrological systems, influencing water availability, quality and ecosystem sustainability. To maintain drinking water resources and ecosystem health, a mechanistic understanding of the underlying processes controlling the spatial patterns and temporal dynamics of groundwater–surface water interactions is crucial. Understanding these interactions requires a multidisciplinary approach that integrates insights from hydrology, geology, ecology, and geochemistry. Several software applications are available to model and analyze these interactions. This abstract presents the framework and key findings of a comprehensive study aimed at elucidating the complex dynamics of surface water-groundwater interactions through different software. Key finding highlights the significance of spatial and temporal variability in surface water-groundwater interactions, emphasizing the need for comprehensive monitoring networks and advanced modeling tools. It underscores the interconnected nature of surface water and groundwater resources, emphasizing the importance of integrated management strategies for sustainable water resource utilization and ecosystem health. It provides an overview of current research advances and innovative approaches in the broad field of surface water-ground water interactions. By adopting a multidisciplinary approach, we can understand the complex interactions shaping the surface water-groundwater systems, facilitating informed decision-making and effective resource management in a dynamic environment.

Facet and dual vacancy engineering-boosting BiOBr for enhanced CO2 and epoxide cycloaddition reaction under mild and cocatalyst-free conditions: Double substrate active sites and activated surface bromine ions synergy

Among the many strategies for CO2 resource utilization, the synthetic technology of cyclic carbonates with 100 % atom economy through CO2and epoxide is one of the most industrially viable routes, but its efficiency has been severely hampered by the lack of highly active catalytic sites. Moreover, due to the intrinsic thermodynamic stability and kinetic inertia of CO2 and the higher energy barrier of the ring-opening reaction of epoxides, the heterogeneous catalytic conversion of CO2 highly depends on harsh operating conditions, high temperatures and pressures, and the incorporation of cocatalysts. The development of efficient heterogeneous catalysts for CO2 conversion under cocatalyst-free and mild conditions has always been a challenge. Herein, we have proposed a synergetic strategy of facet and vacancy engineering for the construction of highly efficient heterogeneous catalyst BiO1-xBr1-y-(010) for CO2 cycloaddition, where introducing the OVs-BrVs pairs into typical (010) facets BiOBr with simultaneous surface Lewis acid sites Bi3+ and nucleophilic sites Br−. By combining theoretical calculations and a series of systematic experiments, such as CO2 temperature-programmed desorption, electron paramagnetic resonance and fluorescence probe analysis experiments, the introduced OVs-BrVs pair can not only form Bi3+-Bi(3-x)+ dual active sites on the surface, which activate PO and CO2 respectively to reduce the energy barrier of CO2 insertion, but also activate Br− near BrVs to enhance their nucleophilic attacking ability and reduce the energy barrier of epoxides ring-opening. As a result, the BiO1-xBr1-y-(010) with abundant surface OVs-BrVs pairs showed a high cyclic carbonates conversion of 99 % with 100 % selectivity under cocatalyst-free and mild conditions, far surpassing most heterogeneous catalytic systems. This work provides a completely new strategy to construct high-performance heterogeneous CO2 cycloaddition catalysts through a simple facet and vacancy engineering strategy to overcome the harsh operating conditions limitation and the use of cocatalysts.

Colloidal interaction of fly ash and soil clay

The combustion of coal worldwide creates a large quantity of fly ash (FA), and the application of FA to agricultural soils is being encouraged as a resource utilization strategy. While most of our attention has focused on positive aspects such as nutrient supplementation and pollution mitigation, the negative impacts of FA have likely been overlooked. In this study, we examined the colloidal properties of FA and soil clay, aiming to demonstrate the ability of FA to increase the dispersibility and transportability of soil clay. Dynamic light scattering technique was coupled with the test tube method to track the kinetics and pH-dependent changes in the zeta potential, hydrodynamic size and colloidal stability of FA, soil clay and their mixtures. We found that FA occurred in solution as “negatively charged balls”, and its negative surface charges increased with increasing pH. FA itself showed a low dispersibility; however, FA became more dispersive when it was introduced to clay suspensions. The mechanism is that the introduction of FA supplied more negative charges to the clay suspension, inducing electrostatic repulsion with soil clay, from which both FA and soil clay were favoured to disperse. Therefore, it can be inferred that off-site transport of FA is possible. More importantly, excessive application of FA can inadvertently intensify clay dispersibility, eventually resulting in soil clays together with FA being more vulnerable to leaching and/or surface run-off erosion. This suggests that the application of FA needs more careful consideration, and the development of more suitable techniques for the sustainable application of FA is still needed.

Novel Insights into Alkyl Polyglucoside Biosurfactant Promoting Anaerobic Dark Fermentation for Hydrogen Production in Sludge.

Anaerobic fermentation of excess sludge (ES) for hydrogen production is a crucial strategy for resource utilization and environmentally friendly treatment. However, the low hydrolysis efficiency of ES and the depletion of produced hydrogen have become the limiting factors for low hydrogen yield. This study innovatively applied the bio-based surfactant alkyl polyglucoside (APG) to enhance the efficiency of dark fermentation for hydrogen production from ES. When the APG content was 100mg/g (calculated based on total suspended solids), the maximum hydrogen production reached 17.8 mL/g VSS, approximately 3.7 times that in the control group. Mechanistic analysis revealed that APG promoted the release of organic matter from ES. APG also facilitated the release of soluble protein and soluble polysaccharide, increasing the organic matter reduction rate to 34.8%, significantly higher than other groups. APG enhanced the accumulation of volatile fatty acids and promoted the proportion of small molecular carboxylic acids. Enzyme activity analysis revealed that APG promoted the activity of hydrolytic enzymes but inhibited the activity of hydrogen-consuming enzymes. The research results provide a green and environmentally friendly strategy for the efficient resource utilization of ES.

Synergistic utilization of cold caustic extraction and deep eutectic solvent for the production of dissolving pulp from corn stalks

This study aimed to produce high-performance dissolving pulps from corn stalks using a combination of cold caustic extraction (CCE) and deep eutectic solvent (DES) method. Results showed that CCE not only removed hemicelluloses but also altered the structure of cellulose, increasing its polymerization degree and influencing the Fock reactivity of the dissolving pulp (reduced to 10.55%). Subsequent treatment with DES effectively dissolving the remaining hemicelluloses while disrupting the cellulose crystallinity and improving the Fock reactivity of the dissolving pulp (increased to 72.14% from 10.55%). The study implied that the hydrogen bond donor in DES played a crucial role in breaking the cellulose chains and improving the reactivity of the dissolving pulp. The dissolving pulp produced from corn stalks using through the combination of CCE and DES method exhibited the cellulose content of 94.46% and the Fock reactivity of 72.14%, providing a new strategy for the high-value utilization of stover resources.

Rethinking urban spatial resource allocation during public health emergencies: assessing comfortable quarantine environment in Guangzhou Hotels

ABSTRACT In response to public health emergencies, many regions have requisitioned daily travel hotels as temporary quarantine places. However, few previous studies examine this policy and reflect on the rationality of urban spatial resource allocation and utilization in terms of comfort during quarantine. This study uses a hybrid multi-attribute decision-making model, based on the collection of 438 pieces of evaluation data about the comfort of isolation hotels in Guangzhou, to build an evaluation framework for the comfort of the quarantine environment. Then, this study uses the ANP-V technique to complete the performance evaluation of selected cases and combines the epidemic spread data in Guangzhou to explore the rationality and improvement strategies of local government epidemic prevention resource allocation and utilization. Based on the results of this study, local decision-makers can optimize the allocation of future epidemic prevention resources and minimize the negative impact on personal health during the emergency period.

Stakeholder engagement in advancing sustainable ecotourism: an exploratory case study of Chilika Wetland

Ecotourism, over time, has emerged as a preferred strategy for resource utilization within protected areas of developing nations, as it effectively bridges the gap between ecological conservation imperatives and the imperative for local economic development. This study aims to comprehensively analyze the multifaceted impacts of ecotourism on local communities, with due consideration given to its environmental, social, and economic dimensions. Furthermore, the research endeavors to evaluate the degree of stakeholder engagement in fostering sustainable tourism practices within ecotourism initiatives. Thematic content analysis has been used and the data for the analysis has been sourced through field observations, key informant discussions and different secondary sources. This research examines the dynamic interaction between local communities and ecotourism aspects in the Chilika Wetland in India, using the DPSIR (Driver-Pressure-State-Impact-Response) framework. It promotes a comprehensive decision-making method that considers the Triple Bottom Line and Community-oriented Collaborative approach. Findings underscore the potential for Chilika’s ecosystem restoration and mitigating adverse tourist impacts with effective ecotourism governance. The need for collaboration among stakeholders becomes crucial for the effective administration of ecotourism, as shown by the instance of Mangalajodi, which exemplifies the successful outcome of community-led ecotourism. Nevertheless, certain prerequisites, such as knowledge dissemination, training, financial support, cultural promotion, eco-friendly infrastructure, and a commitment to conservation, have been recognized as necessary for ensuring long-term community involvement in ecotourism initiatives.

Beneficiation process reengineering under the background of green development-- take the full utilization of a low-grade lead-zinc ore as an example

A zero-waste mine is an advanced mine development and resource utilization strategy that aims to encourage the reduction of mine solid waste at source and the utilization of all its components. A low-grade lead-zinc ore in Guangxi, China, contains valuable components like galena, sphalerite, pyrite, barite, etc. and the gangue mineral is primarily dolomite. This paper proposes a flow of “waste pre-discarding by dense medium cyclone - sequential priority flotation of lead and zinc recovery - flotation and gravity combined process for barite recovery” to realize full component utilization. In this technical approach, 38.81% of the waste rock that can be utilized as concrete aggregate was removed from the feed ore through pre-discarding prior to grinding, after that recovers lead and zinc by the sequential priority flotation method with yield of Pb concentrate and Zn concentrate at 7.61%. In order to more efficiently recover barite and pyrite from lead-zinc flotation tailings, the gravity equipment of reflux classifier (RC) was used, which obtained barite concentrate with a yield of 7.97% and pyrite concentrate with a yield of 2.28%. The remaining yield of 43.34% tailings can be used for filling after the recovery of barite concentrate. Utilizing waste rock, lead, zinc, barite, and other resources might help the mine achieve the dynamic balance of “mining-discarding-beneficiation-filling” and realize zero tailings discharge.

餐厨垃圾高温好氧发酵工艺的研究

With the rapid urbanization in China, there has been a gradual increase in the production of kitchen waste, which poses significant environmental challenges. High-temperature aerobic fermentation is an effective method for recycling kitchen waste. This study focuses on utilizing kitchen waste, wood chips, and compound microbial agents as the main raw materials for fermentation. Various parameters such as temperature, moisture content, and amount of compound microbial agent were selected to conduct experiments on the high-temperature stage of the aerobic fermentation process for kitchen waste. Through response surface optimization experiments, it was determined that the optimal conditions for achieving fast high-temperature fermentation of kitchen waste are as follows: temperature at 60℃, moisture content at 60%, and amount of compound microbial agent at 10%. The order of influence on the reduction rate of kitchen waste is found to be temperature followed by the amount of compound microbial agent and moisture content. These findings provide valuable insights into resource utilization strategies for managing kitchen waste.

Shrimp Waste Upcycling: Unveiling the Potential of Polysaccharides, Proteins, Carotenoids, and Fatty Acids with Emphasis on Extraction Techniques and Bioactive Properties.

Shrimp processing generates substantial waste, which is rich in valuable components such as polysaccharides, proteins, carotenoids, and fatty acids. This review provides a comprehensive overview of the valorization of shrimp waste, mainly shrimp shells, focusing on extraction methods, bioactivities, and potential applications of these bioactive compounds. Various extraction techniques, including chemical extraction, microbial fermentation, enzyme-assisted extraction, microwave-assisted extraction, ultrasound-assisted extraction, and pressurized techniques are discussed, highlighting their efficacy in isolating polysaccharides, proteins, carotenoids, and fatty acids from shrimp waste. Additionally, the bioactivities associated with these compounds, such as antioxidant, antimicrobial, anti-inflammatory, and antitumor properties, among others, are elucidated, underscoring their potential in pharmaceutical, nutraceutical, and cosmeceutical applications. Furthermore, the review explores current and potential utilization avenues for these bioactive compounds, emphasizing the importance of sustainable resource management and circular economy principles in maximizing the value of shrimp waste. Overall, this review paper aims to provide insights into the multifaceted aspects of shrimp waste valorization, offering valuable information for researchers, industries, and policymakers interested in sustainable resource utilization and waste-management strategies.

Modifying humus-phosphorus-arsenic interactions in sludge composting: The strengthening of phosphorus availability and arsenic efflux detoxification mechanisms

Arsenic (As) in sewage sludge poses a significant threat to environmental and human health, which has attracted widespread attention. This study investigated the value of adding sodium percarbonate (SP) on phosphorus (P) availability and As efflux detoxification through HS-P-As interactions. Due to the unique structure of humus (HS) and the similar chemical properties of P and As, the conditions for HS-P-As interaction are provided. This study discussed the content, morphology and microbial communities of HS, P and As by using metagenomic and correlation analysis. The results showed that the humification index in the experiment group (SPC) was 2.34 times higher than that in the control group (CK). The available phosphorus (AP) content of SPC increased from 71.09 mg/kg to 126.14 mg/kg, and SPC was 1.11 times that of CK. The relative abundance of ACR3/ArsB increased. Pst, Actinomyces and Bacillus commonly participated in P and As conversion. The correlation analysis revealed that the humification process was enhanced, the AP was strengthened, and the As was efflux detoxified after SP amendment. All in all, this study elucidated the key mechanism of HS-P-As interaction and put forward a new strategy for sewage sludge resource utilization and detoxification.

A regenerative agenda for economic recovery: Nurturing natural resource efficiency to foster environmental, social, and economic well-being

This study investigates the impact of green finance investments on sustainable development across 30 regions in China from 2005 to 2020, focusing on the role of technological advancement and natural resource efficiency in the context of mineral resource investments. Employing Augmented Mean Group (AMG) and Common Correlated Effects Mean Group (CCE-MG) methodologies, we explore the complex interactions between technology development, renewable energy integration, and their implications for sustainable development. Our analysis delves into the nuanced relationship between technological progress in natural resource management and its contributions to economic growth and environmental sustainability. The findings underscore the necessity of a holistic resource utilization strategy, highlighting the critical importance of investments in natural resources for enhancing industrial efficiency and fostering socio-economic advancement. We advocate for a comprehensive investment approach that melds green finance principles with technological innovations to ensure sustainable development throughout the mineral resource exploitation process.

Forest Age Drives the Resource Utilization Indicators of Trees in Planted and Natural Forests in China.

Specific leaf area (SLA) and leaf dry matter content (LDMC) are key leaf functional traits commonly used to reflect tree resource utilization strategies and predict forest ecosystem responses to environmental changes. Previous research on tree resource utilization strategies (SLA and LDMC) primarily focused on the species level within limited spatial scales, making it crucial to quantify the spatial variability and driving factors of these strategies. Whether there are discrepancies in resource utilization strategies between trees in planted and natural forests, and the dominant factors and mechanisms influencing them, remain unclear. This study, based on field surveys and the literature from 2008 to 2020 covering 263 planted and 434 natural forests in China, using generalized additive models (GAMs) and structural equation models (SEMs), analyzes the spatial differences and dominant factors in tree resource utilization strategies between planted and natural forests. The results show that the SLA of planted forests is significantly higher than that of natural forests (p < 0.01), and LDMC is significantly lower (p < 0.0001), indicating a "faster investment-return" resource utilization strategy. As the mean annual high temperature (MAHT) and mean annual precipitation (MAP) steadily rise, trees have adapted their resource utilization strategies, transitioning from a "conservative" survival tactic to a "rapid investment-return" model. Compared to natural forests, planted forest trees exhibit stronger environmental plasticity and greater variability with forest age in their resource utilization strategies. Overall, forest age is the dominant factor influencing resource utilization strategies in both planted and natural forests, having a far greater direct impact than climatic factors (temperature, precipitation, and sunlight) and soil nutrient factors. Additionally, as forest age increases, both planted and natural forests show an increase in SLA and a decrease in LDMC, indicating a gradual shift towards more efficient resource utilization strategies.

Rapid removal of ofloxacin with peroxymonosulfate activation process mediated by Co3O4/Sludge-derived biochar composite: Unveiling the enhancement of biochar

In this study, sludge-derived biochar loaded Co3O4 composite (Co3O4@SDBC) were successfully synthesized through cobalt impregnation and secondary calcination of sludge-derived biochar precursors. The experimental results demonstrated that the Co3O4@SDBC catalyst performed exceptionally well for peroxymonosulfate (PMS) activation, with a high degradation efficiency (>99 %) of ofloxacin (OFL) within 10 min under the optimal conditions (a catalyst dose of 0.10 g•L−1, a PMS dose of 0.975 mM and an initial pH = 6.4), and showed good adaptability across a broad pH spectrum, under the interference of the anions and humic acid (HA), as well as in various water matrices. The results of quenching experiments revealed that the non-radical pathway (especially 1O2 and electron transfer) was the dominated reactive ingredients in the PMS activation process induced by Co3O4@SDBC. Notably, the online electrochemical tests and density functional theory (DFT) results indicated the presence of biochar carrier not only effectively lowered the escape of Co ions, while enhanced the steadiness of Co3O4@SDBC, but also accelerated the electron transfer, promoted the adsorption and cleavage of PMS, facilitated the redox cycle between Co(II) and Co(III), reduced the reaction energy barriers simultaneously, thereby making it more favourable for the generation of 1O2. Furthermore, the toxicity assessment suggested that the cumulative toxicity of OFL decreased throughout degradation. Overall, this work mechanistically revealed the enhancement of biochar on the Co3O4@SDBC catalyst, offering a viable method to activate PMS for antibiotic removal and achieving a mutually beneficial strategy for sludge waste resource utilization and environmental remediation.

Highly efficient elimination of organic contaminants by boron-doped biochar modified dual-cathode electro-Fenton system

Electro-Fenton (EF) process stands out as an energy-efficient and highly promising advanced oxidation technology for organic contaminants degradation. However, achieving optimal heterogeneous catalytic conditions for simultaneous H2O2 generation and spontaneous Fe2+ regeneration poses difficulties in conventional EF. This is due to the electric potential difference between H2O2 generation and Fe2+ regeneration at a single cathode. Therefore, the boron doped biochar modified dual-cathode EF (DCEF) system was designed in this work to overcome the defect of conventional EF system, which not only demonstrated outstanding accumulation of H2O2 (>300 mg L-1) but also exhibited a remarkable capability of degradation (>90 %). Furthermore, the system could also adapt to a broad pH range of 3–11. The superior doxycycline (DOX) degradation efficiency of DCEF system could be attributed to the dominant role played by C=O and BCO2 groups in the activation of H2O2 and subsequently generating reactive oxygen species (ROSs), as revealed by XPS analysis and DFT calculation. In addition, the DCEF system achieved an impressive TOC removal efficiency of 70.5 % and a minimal energy consumption (EC) of 0.32 kWh (g TOC)-1. Therefore, this work introduced a DCEF system to address the challenges of conventional EF system, which shed light on the design of wastewater treatment technology and lied the groundwork for a strategy of resource utilization.

Integrated watershed management strategies for sustainable resource utilization using the SWAT model: case study of the Kalte River watershed, Rift Valley Basin, Ethiopia

ABSTRACT Most people who live in rural areas are highly dependent on shared access to natural resources including land, water, and forests for their food requirements and livelihoods. However, land degradation remains one of the biggest environmental problems worldwide. Therefore, this study proposed to develop integrated watershed management strategies for sustainable resource utilization in the Kalte River watershed. To achieve this, the SWAT model was simulated for 31 years (1992–2022), calibrated and validated at Wajifo and Humbo hydrological stations to determine the sediment and runoff from the watershed, highly sediment erosion-vulnerable part of the watershed was identified from the result of the model and the best watershed management practice was suggested for the study watershed. In total, 87,920 tons/year of sediment are yielded to Lake Abaya from the Kalte River watershed. The sediment yield was reduced by terracing at 64%, strip cropping at 59.32%, grassed waterway at 54.06%, and contour planting at 47.93%. Therefore, the highest efficiency management method in the Kalte River watershed is terracing. The watershed managers and scientific community are beneficiaries of the output of this study. Watershed managers and decision-makers can make use of the information to help them choose appropriate watershed management strategies and ensure sustainable watershed management.

Porphyrin-functionalized non-magnetic steel slag as bifunctional nanozymes for colorimetric detection and photocatalytic degradation of tetracycline

Inspired by natural enzymes with various activities, controlling the catalytic activity of nanozymes through suitable strategies has received extensive attention. By modifying non-magnetic steel slag material (NMSS) with porphyrin, we developed a new kind of bifunctional nanozymes (NMSS-Por) with both simulated enzyme activity and photocatalytic activity. The NMSS-Por nanozymes exhibit outstanding colorimetric sensing and photodegradation performances, with a limit of detection (LOD) of 0.257 µM, 0.102 µM and 0.142 µM for tetracycline (TC), oxytetracycline, and doxycycline, while a removal rate of 79 % for TC after 60 min. Hydroxyl radical (·OH), positively charged hole (h+), singlet oxygen (1O2), and photogenerated electron transfer process play vital roles in both catalytic reactions. Besides, NMSS-Por nanozymes has excellent selectivity for TC detection and can also be used as promising photocatalysts for real water treatment. This work provides a new and promising strategy for the high value-added resource utilization of waste steel slag in environmental catalysis, which is in accordance with the sustainable development of green chemistry.