Physics and Chemistry of the Earth最新文献

{"title":"Performance of sulfate species on limestone powder concrete under low temperature pulse current","authors":"Chenjie Wu ,&nbsp;Lingchen Meng ,&nbsp;Dezhi Wang ,&nbsp;Haiwei Zhang ,&nbsp;Long Ke ,&nbsp;Zhipeng Ma","doi":"10.1016/j.pce.2024.103850","DOIUrl":"10.1016/j.pce.2024.103850","url":null,"abstract":"<div><div>The leakage phenomenon of subway trains in urban subway systems can accelerate the erosion and damage of concrete structures, which has adverse effects on the safety and service life of the project. This study aims to evaluate the erosion effect of sulfate solution on concrete by simulating the low temperature pulse current conditions on subway tracks. The erosion mechanism of sulfate solution on limestone powder concrete under low temperature pulse current was revealed through macroscopic methods such as surface morphology observation, compressive strength testing, and sulfate ion content analysis. Further analysis of the degradation mechanism was conducted using SEM, porosity measurement, and microhardness testing. The results showed that pulse current promoted the migration and enrichment of SO₄²⁻ towards the cathode in limestone powder concrete, forming a large amount of hydration products such as Mg(OH)₂, gypsum, and ettringite, which blocked the pores. Although the impact of sulfate type on quality loss is limited, the compressive strength of all test blocks usually decreases, with a compressive strength loss rate of 22.8% for the C1 group of cubic test blocks. During the erosion process, the content of SO₄²⁻ decreases with increasing depth, and there is almost no SO₄²⁻ in the center of the test block. The porosity decreases with erosion depth, and the anode region is higher than the cathode. The damage caused by sulfate erosion does not differ significantly between different solutions, but the hardness of the anode is slightly higher than that of the cathode.</div></div>","PeriodicalId":54616,"journal":{"name":"Physics and Chemistry of the Earth","volume":"138 ","pages":"Article 103850"},"PeriodicalIF":3.0,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143167803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluating the influence of biophysical factors in explaining spatial heterogeneity of LST: Insights from Brahmani-Dwarka interfluve leveraging Geodetector, GWR, and MGWR models","authors":"Bhaskar Mandal,&nbsp;Kaushalendra Prakash Goswami","doi":"10.1016/j.pce.2024.103836","DOIUrl":"10.1016/j.pce.2024.103836","url":null,"abstract":"<div><div>The present study aims to investigate variations in land use and land cover (LULC) while examining how land surface temperature (LST) and biophysical parameters in the Brahmani-Dwarka Interfluve zone change over time. It also tries to discover LST clusters and outliers and investigate how biophysical variables influence the spatially stratified heterogeneity of LST. This study introduces an innovative perspective by concentrating on the Brahmani-Dwarka Interfluve, an area characterized by stone crushing and mining operations. It employs Geodetector, Geographically Weighted Regression (GWR), and Multiscale Geographically Weighted Regression (MGWR) to thoroughly evaluate the LST heterogeneity, thereby enhancing its uniqueness. Our analysis revealed LST saw a substantial rise of 7.05 °C, equivalent to an average yearly increase of around 0.235 °C between 1991-2021. The regions primarily occupied by stone crushing and mining activities showed elevated LST values compared to other LULC categories in the years 2001, 2011, and 2021. The factor detector findings suggested that the Normalized Difference Latent Heat Index (NDLI) had the most influence in 2001 (q-value 0.39) and 2021 (q-value 0.50), whereas the Normalized Difference Moisture Index (NDMI) had the highest influence in 1991 (q-value 0.39) and 2011 (q-value 0.29). Soil-adjusted Vegetation Index (SAVI) had the most negligible influence (q-value between 0.09-0.15). The Interaction detector findings identified NDLI with NDMI (q-value 0.42) and Modified Normalized Difference Water Index (MNDWI) (q-value 0.42) in 1991, NDLI with Normalized Difference Bareness Index (NDBaI) (q-value 0.41) and MNDWI (q-value 0.41) in 2001, and NDLI with Normalized Difference Vegetation Index (NDVI) (q-value 0.56) and SAVI (q-value 0.56) in 2021 as the most influential interacting variable. In 2011, significant interactions were identified between MNDWI and NDVI (q-value 0.31), NDMI, and SAVI (q-value 0.31), among others. A comparative assessment between regression models using AICc, R², and adjusted R² revealed that all MGWR models performed (R² between 0.92-0.94 &amp; adj. R² between 0.89-0.92) much better than GWR and Ordinary Least Square (OLS) models during the research period. The results will undoubtedly assist policymakers, environmentalists, and stakeholders by providing valuable insights for enhancing environmental management and policies.</div></div>","PeriodicalId":54616,"journal":{"name":"Physics and Chemistry of the Earth","volume":"138 ","pages":"Article 103836"},"PeriodicalIF":3.0,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143167804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An assessment of the drainage system and waterlogging at the Silalabuhwa irrigation scheme","authors":"Onias Chikwanda,&nbsp;Bright Chisadza,&nbsp;Canisius Mpala","doi":"10.1016/j.pce.2024.103837","DOIUrl":"10.1016/j.pce.2024.103837","url":null,"abstract":"<div><div>This study investigates the threats posed by waterlogging and salinization to agricultural productivity at the Silalabuhwa Irrigation Scheme in Zimbabwe. To assess these threats, soil samples (n = 20) were collected from both waterlogged and non-waterlogged areas within irrigation blocks and analyzed for texture, pH, and electrical conductivity (EC). Water samples from the dam and canal were similarly analyzed for pH, turbidity, and EC. Additionally, key informant interviews provided valuable insights into the extent and causes of waterlogging, along with potential solutions. Slope analysis and mapping of waterlogged areas were conducted using topographical tools and GPS technology. The findings reveal a significant challenge, with 87.96 ha of land affected by waterlogging, which consequently reduces the available area for irrigated agriculture. Areas with non-functional drainage systems exhibited the most severe waterlogging, highlighting deteriorating infrastructure and poor water management practices as the primary culprits. To address these issues and ensure the scheme's long-term sustainability, the study proposes a multi-pronged approach including rehabilitation of irrigation infrastructure, leaching of excess salts from the soil, staff training on improved irrigation practices, and the implementation of a water-efficient irrigation system equipped with sensors to precisely control water application. By implementing these recommendations, this study aims to contribute to improved land use efficiency, enhanced crop yields at Silalabuhwa Irrigation Scheme, and ultimately, regional food security.</div></div>","PeriodicalId":54616,"journal":{"name":"Physics and Chemistry of the Earth","volume":"138 ","pages":"Article 103837"},"PeriodicalIF":3.0,"publicationDate":"2024-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143167319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cross-modal fusion approach with multispectral, LiDAR, and SAR data for forest canopy height mapping in mountainous region","authors":"Petar Donev ,&nbsp;Hong Wang ,&nbsp;Shuhong Qin ,&nbsp;Xiuneng Li ,&nbsp;Meng Zhang ,&nbsp;Sisi Liu ,&nbsp;Xin Wang","doi":"10.1016/j.pce.2024.103819","DOIUrl":"10.1016/j.pce.2024.103819","url":null,"abstract":"<div><div>The study introduces a technique for integrating multispectral, LiDAR, and Synthetic Aperture Radar (SAR) data within a machine-learning (ML) framework. By leveraging ML models, including Random Forest (RF), Gaussian Process Regression (GPR), and k-Nearest Neighbors (k-NN), successfully provides a comprehensive methodology for mapping forest canopy height (CH) and analyzes seasonal changes from 2019 to 2023 in the mountainous region of Vodno Mountain, North Macedonia. The RF model achieved the highest accuracy (R² = 0.91, RMSE = 1.2 m), outperforming the other models when trained with Aerial LiDAR data. The forest CH models were validated against field measurements, Aerial LiDAR, and Global Ecosystem Dynamics Investigation (GEDI) data, confirming the accuracy of the approach and showing solid correlations between predicted and observed CH values. This research is significant due to its innovative approach to forest CH modeling in a region with minimal prior studies. Integrating multi-source data enables more accurate and detailed CH mapping, essential for monitoring forest biomass and carbon stocks, detecting forest disturbances, and assessing future forest management activities.</div></div>","PeriodicalId":54616,"journal":{"name":"Physics and Chemistry of the Earth","volume":"137 ","pages":"Article 103819"},"PeriodicalIF":3.0,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142745230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Radiological hazards associated with natural radioactivity in topsoil and subsoil from Osogbo, Nigeria","authors":"Hyam Khalaf ,&nbsp;M.A. Olaoye ,&nbsp;Mostafa.Y.A. Mostafa ,&nbsp;R.B. Adegbola ,&nbsp;E.D. Muniru ,&nbsp;Howaida Mansour","doi":"10.1016/j.pce.2024.103821","DOIUrl":"10.1016/j.pce.2024.103821","url":null,"abstract":"<div><div>The present research used gamma-ray spectrometry to assess the amount of activity concentration for radionuclides (²²⁶Ra, ²³²Th and ⁴⁰K). That naturally exist in samples of topsoil and subsoil in Osogbo, Osun State, Nigeria, using a sodium-iodide detector and associated radiological risk factors were estimated. The activity levels of ²²⁶Ra, ²³²Th and ⁴⁰K are, respectively, ranges from 167.03 ± 4.37 to 1187.51 ± 178.68 Bqkg⁻¹, 18.21 ± 23.97 to 134.79 ± 60.00 Bqkg⁻¹ and 8.67 ± 4.80 to 188.65 ± 7.33 Bqkg⁻¹ for subsoil, and ranges from 263.64 ± 5.39 to 3303.33 ± 14.47 Bqkg⁻¹, 23.90 ± 32.28 to 191.05 ± 72.93 Bqkg⁻¹ and 9.90 ± 5.90 to 129.17 ± 8.94 Bqkg⁻¹for topsoil. According to the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), the global average activity levels for these radionuclides are ²²⁶Ra (35 Bq/kg), ²³²Th (30 Bq/kg), and ⁴⁰K (400 Bq/kg). In the study area, the average activity levels of these radionuclides were found to be higher in subsoil compared to topsoil. The estimated average of radiological risk factors (radium activity, the absorbed dose rate, annual gonadal dose equivalent, excess lifetime cancer risk, and representative level index) are recorded, 166.52 Bq/kg, 78.62 nGy/h, 545.23 μSv/y, 0.38 and 1.21 For subsoil respectively, but for topsoil are recorded 184.39 Bq/kg, 90.39 nGy/h, 637.92 μSv/y, 0.44 and 1.40 respectively. All radiological risk factors are much greater than those reported by UNSCEAR (2000) magnitudes of 370 Bq/kg, 59 nGy/h, 300 μSv/y, 2.9 × 10-4, and 1, respectively. The results obtained reveal a high radioactivity level in the investigated area. Therefore, it is advised that the study region have regular radiation monitoring and ecological evaluations.</div></div>","PeriodicalId":54616,"journal":{"name":"Physics and Chemistry of the Earth","volume":"137 ","pages":"Article 103821"},"PeriodicalIF":3.0,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142745229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of groundwater potential zones for hard rock area of sabi river basin using an integrated approach of remote sensing, GIS and AHP techniques","authors":"Sachin L. Suryawanshi ,&nbsp;Pradeep Kumar Singh ,&nbsp;Mahesh Kothari ,&nbsp;Manjeet Singh ,&nbsp;Kamal Kishore Yadav ,&nbsp;Trilok Gupta","doi":"10.1016/j.pce.2024.103820","DOIUrl":"10.1016/j.pce.2024.103820","url":null,"abstract":"<div><div>The study was conducted to assess groundwater potential zones (GWPZs) for hard rock area of Sabi river basin for the sustainable development. Remote Sensing (RS) and Geographic Information System (GIS) have emerged as crucial methods in retrieval, monitoring and conserving groundwater resources were used along with Analytical Hierarchy Process (AHP) to demarcate the GWPZs. In order to assess GWP in the study area, eight thematic maps: drainage density, geomorphology, geology, rainfall, land use/land cover, lineament density, slope and soil were prepared using RS and conventional data. The AHP was applied to assign the weightages for each thematic map and its sub classes. Then, the thematic layers were overlaid using the weighted overlay analysis means of ArcGIS 10.4 to assess the GWPZ map of Sabi basin. The Sabi basin was categorized into five classes of GWPZ as very good (0.01%), good (24.72%), moderate (56.54%), poor (10.45%) and very poor (8.28%). The accuracy of produced GWPZ map was assessed with well yield data by agreement scheme using ground water prospects map and by using ROC curve analysis through R-studio software which indicates the satisfactory GWPZ map prediction accuracy. This study provides valuable database in planning and development of groundwater recharging and to delineate locations of potential artificial recharge sites in the hard rock regions and semi -arid areas so that appropriate structures could be planned and constructed to manage aquifer recharge for sustainable groundwater management in the future.</div></div>","PeriodicalId":54616,"journal":{"name":"Physics and Chemistry of the Earth","volume":"137 ","pages":"Article 103820"},"PeriodicalIF":3.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142745226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamic coupling coordination of territorial spatial development intensity and comprehensive disaster-carrying capability: A case study of Beijing-Tianjin-Hebei urban agglomerations, China","authors":"Wei Wang ,&nbsp;Qianqian Guo,&nbsp;Pei Yang,&nbsp;Chenhong Xia","doi":"10.1016/j.pce.2024.103818","DOIUrl":"10.1016/j.pce.2024.103818","url":null,"abstract":"<div><div>The effectiveness of the modernization of the governance system is significantly impacted by the interaction between the territorial spatial development intensity (TSDI) and the comprehensive disaster-carrying capacity (CDCC). It is of great significance to investigate the intrinsic interaction between the TSDI and the CDCC. Identifying the disaster risks induced by the intensity of the territorial spatial development and their constraints promotes synergistic development to cope with the uncertainty. The study explored the degree of coupling, the level of coordinated development, and the dynamic development trend between TSDI and CDCC from the perspective of coupling coordination. Beijing-Tianjin-Hebei (BTH) Region was used as a case study and it was found 1) there is a higher degree of coupling, and high correlation between TSDI and CDCC in the BTH urban agglomeration region; 2) the BTH region has the highest number of cities with coordination levels on the verge of maladjustment, followed by ones with barely coordinated cities; 3) while the overall level of coordination gradually increases, the overall deviation degree of development of TSDI and CDCC in the BTH urban agglomeration region is gradually decreasing; 4) there is an interactive coercion relationship between TSDI and CDCC in the BTH urban agglomeration region. This study may help provide a decision-making basis for the BTH urban agglomeration on improving the pertinence of urban disaster prevention and mitigation construction, adjusting the spatial structure of the national territory, and promoting the coordinated development of different cities. Moreover, technical support and theoretical guidance for similar regions was also developed to assess the land suitability, establish an integrated defense system of the national territory and space, and exercise resilient city planning.</div></div>","PeriodicalId":54616,"journal":{"name":"Physics and Chemistry of the Earth","volume":"137 ","pages":"Article 103818"},"PeriodicalIF":3.0,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142723604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improvability of quality main indices of a marl soil using endemic microorganisms","authors":"Atefeh Jafarpoor ,&nbsp;Seyed Hamidreza Sadeghi ,&nbsp;Mehdi Homaee ,&nbsp;Behrouz Zarei Darki","doi":"10.1016/j.pce.2024.103812","DOIUrl":"10.1016/j.pce.2024.103812","url":null,"abstract":"<div><div>Biological soil crusts are essential for ecosystem productivity in arid and semiarid regions, where cyanobacteria (Cy) and bacteria (Ba) are pivotal. These microorganisms enhance nutritional conditions, soil stability, soil fertility, and forage quality through the secretion of polysaccharides. However, there is a lack of comprehensive quantitative studies addressing the changes in soil's physical and chemical properties. This research investigated the impact of individual and combined inoculations of Cy and Ba on the rangeland quality of low-quality soil in the Marzanabad region. The indicators of soil quality assessed included carbon (C) content, nitrogen (N) levels, C/N ratio, soil-available phosphorus (P), and aggregate stability. The findings indicated that microbial inoculation significantly (p &lt; 0.01) affected N concentration, available P, and aggregate stability. Additionally, the individual and combined treatments of Cy and Ba resulted in increases in C content of 57.14%, 297.14%, and 120%, respectively, compared to the control. The N concentration in these treatments was 150%, 37.50%, and 325% higher than that of the control soil. In terms of absorbable P, increases of 105.48%, 6.54%, and 39.57% were observed compared to the control conditions. Furthermore, the superficial inoculation of microorganisms enhanced aggregation adhesion, with stability in the individual and combined Cy and Ba treatments increasing by 29.20%, 61.65%, and 42.11%, respectively, relative to the control treatment. The results of this study suggest that utilizing soil microorganisms to restore plant cover in arid and semiarid regions is a viable strategy.</div></div>","PeriodicalId":54616,"journal":{"name":"Physics and Chemistry of the Earth","volume":"137 ","pages":"Article 103812"},"PeriodicalIF":3.0,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142705048","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of multi-objective Harris hawks optimization (MOHHO) algorithm in low-impact development systems considering the effects of climate change","authors":"Manizheh Pourali Dougaheh ,&nbsp;Parisa-Sadat Ashofteh","doi":"10.1016/j.pce.2024.103816","DOIUrl":"10.1016/j.pce.2024.103816","url":null,"abstract":"<div><div>In this research, to control and manage basin runoff by using Low-Impact Development (LID) systems in climate change conditions, a simulator-optimizer model is developed using the SWMM model and the MOHHO algorithm. Four LIDs of vegetative swale, bio-retention cell, permeable pavement, and infiltration trench have been used. Therefore, the areas of LIDs are determined in the sub-basins of Zone 1 and 3 of Tehran Municipality for the periods of the baseline (1988–2005), the near future (2030–2047), and the far future (2048–2065), with the objectives of (1) minimizing the cost of implementing and maintaining LIDs, (2) minimizing the amount of outflow runoff of the basin. In this research, the future rainfall under three emission scenarios RCP2.6, RCP4.5, and RCP8.5 has been simulated. By comparing the convergence diagram of MOHHO with the NSGAII algorithm, it was observed that the MOHHO has more dispersion of solutions and less run-time. Finally, with the help of this model, optimal management solutions were obtained in the form of the Pareto front. The results show that the flood volume was reduced by 50% on average compared to not using the system, considering the objective function of minimizing the outflow flood volume of the basin. But this value is reduced by 30% by giving importance to the second objective function, which is to minimize costs. Finally, due to the reduction of cost and economic efficiency, the implementation and use of these systems can be justified and have a significant effect in reducing the problems of the region.</div></div>","PeriodicalId":54616,"journal":{"name":"Physics and Chemistry of the Earth","volume":"137 ","pages":"Article 103816"},"PeriodicalIF":3.0,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142705050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Adsorption of hexavalent chromium from wastewater using magnetic biochar derived from peanut hulls","authors":"Lehlogonolo Tabana,&nbsp;Annita Kupa,&nbsp;Shepherd Tichapondwa","doi":"10.1016/j.pce.2024.103815","DOIUrl":"10.1016/j.pce.2024.103815","url":null,"abstract":"<div><div>In this study, the utilization of peanut hulls as a precursor for the preparation of magnetic biochar through pyrolysis was investigated. To enhance the magnetic and adsorption properties of the biochar, the peanut hulls biomass was modified using ferric chloride hexahydrate and magnesium chloride hexahydrate. Response surface methodology was employed to evaluate the influence of biomass metal concentration, pyrolysis temperature, pyrolysis period and flow of nitrogen on the yield and Cr (VI) adsorption efficiency of the synthesized biochar. A 17-run experimental matrix was generated using Optimal Design to investigate the interactions among four input parameters. The results led to the development of a quadratic model, which demonstrated a high degree of predictability in accordance with the experimental data. Analysis of variance (ANOVA) confirmed that the models for yield and Cr (VI) adsorption efficiency were highly significant (p &lt; 0.05), with coefficients of determination (R²) values of 0.891 and 0.988, respectively. The optimal synthesis conditions for producing biochar with superior physicochemical properties were identified as a pyrolysis temperature of 300 °C, a pyrolysis duration of 2 h, a metal-to-biomass ratio of 0.5, and a constant flow of nitrogen. A desirability of 85% was achieved through numerical optimization, corresponding to a yield of 63% and complete Cr (VI) removal. Further optimization of Cr (VI) adsorption efficiency, considering the effects of pH (3–12), adsorbent loading (1–15 g/L), and initial Cr (VI) concentration (5–20 mg/L), was performed using a 19-run experimental matrix. ANOVA for Cr (VI) adsorption efficiency model revealed high significance (p &lt; 0.05) with an R² value of 0.916.</div><div>The magnetic biochar demonstrated a remarkable adsorption efficiency of 98% under the experimental conditions of solution pH 3, adsorbent dosage of 5 g/L, and an initial Cr (VI) concentration of 20 mg/L. The desirability of 100% was obtained by a numerical optimization method representing Cr (VI) removal of 98%. The adsorption behaviour was adequately described by the Freundlich isotherm model, suggesting multilayer adsorption, with a maximum adsorption capacity of 12 mg/g. Biochar also proved to have strong magnetic properties which enhanced solid-liquid separation post adsorption experiments.</div></div>","PeriodicalId":54616,"journal":{"name":"Physics and Chemistry of the Earth","volume":"137 ","pages":"Article 103815"},"PeriodicalIF":3.0,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142705045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}