Competitive Research Articles

Materials Design for Critical Element Separation

The development of renewable energy technologies and next-generation optoelectronic devices relies on the secured supply of critical elements (such as lithium and rare earth element). Traditional mining and separation methods are disruptive to the environment, consume large quantities of harsh chemicals, and are unable to access dilute resources due to low elemental selectivity. Therefore, the invention of new separation methods and the fundamental understanding of the separation processes are crucial to realizing sustainable mining while broadening minable resources. In this talk, I will introduce a platform method, electrochemical intercalation, for selective ion separation using lithium extraction as an example. I will explain the different roles of major ions in competition with lithium ion and discuss strategies to promote lithium intercalation during co-intercalation by materials design.

Pendampingan Baca Puisi dalam Rangka Lomba FLS2N Kabupaten Trenggalek Tahun 2024

Poetry as a form of literary work includes a variety of feelings. The role of poetry is very large, given that poetry has a very large impact on life in society. Regarding poetry that is read or performed in a competition event as big as FLS2N means that it also provides a separate experience for connoisseurs of this type of literary work. Literary works of poetry give literary connoisseurs a taste of their own. The holding of this poetry reading competition event makes poetry reading at the school level grow and develop. In addition, the activity becomes a spectacle as well as an achievement event for the school.

THE RIGHT TO RIDE: AN ETHNOGRAPHY OF AN URBAN AND MARGINAL PRACTICE

This text discusses structural aspects of the practice of roller-cart, based on an ethnography conducted in the Metropolitan Region of Belo Horizonte between 2019 and 2022. Initial impressions indicated that the roller-cart movement, with competition teams, associations and event organizers in the city, was a large and coordinated action of a cohesive group of people around the same purpose. With a dense and prolonged stay in the field, I found a movement marked by disputes, interests and multiple appropriations that limit, at the same time as they shape, a community of practice that emerges from a collective, urban and marginal construction. In this sense, this text highlights three structural aspects of the practice of roller-cart: the participation of women in events, based on the notion of the sexed city by Michele Perrot; the territorial disputes of these groups with the orders of the State and Capital, from the perspective of the city as a right, by Henri Lefebvre; and the search for legitimacy of a marginalized practice, through the prism of consumption as a constituent of identities, according to Michel de Certeau. Thus, men and women, adults and children, participate, constitute, and are constituted by a polysemic, contradictory, and essentially situated practice.

Comparative Investigation of Differential Mood Responses among Elite, Non-Elite, and Non-Athletes in Total Lockdown

The onset of the COVID-19 global health crisis, marked by stringent restrictions on training routines and sudden cancellations of competitive events, precipitated abrupt and radical transformations within the sporting landscape. The emergency alert prompted governments worldwide to enforce various lockdown measures to curb the escalation of the viral outbreak. Recognising the potential psychological repercussions of these circumstances, a rapid assessment of mood states as well-being indicators was conducted during the initial months of the lockdown in the Philippines. A cross-sectional study using Tilly’s (1984) variation-finding approach was undertaken to distinguish mood profiles between athletes of different competitive tiers and between athletes and non-athletes. Employing the 16-item version of the Profile of Mood States (POMS-16), mood responses were collected and compared across 705 elite athletes, 1,702 non-elite athletes, and 1,246 non-athletes. Analysis of mean patterns revealed that elite athletes consistently reported greater levels of dejection/anxiety, fatigue, irritability, vigour, and overall mood disturbance than did their non-elite and non-athlete counterparts. The findings affirm the substantial disparities in mood states between athletes of different competitive tiers and between athletes and non-athletes during the pandemic. Nonetheless, despite the elevated scores for negative mood responses, vigour emerged as consistently the highest among all mood responses across all three groups. The results are discussed considering the unique characteristics of elite and non-elite athletes and the protective role of vigour in mental well-being during adversity. By acknowledging athletes' distinct psychological reactions to circumstances hindering competitive sport engagement, this study contributes to understanding how disruptive health crises could affect athletes’ well-being, potentially informing the development of targeted support programmes for athletes confronting similar challenges.

Ion exchange selectivity for protons by sodium ion-form crystalline silicotitanate

ABSTRACT At the Fukushima Daiichi Nuclear Power Station site, crystalline silicotitanate (CST) ion exchangers containing sodium ions (Na+) as exchange ions are used as an adsorbent to remove radioactive cesium (Cs) and strontium (Sr) from groundwater and contaminated water. The ion exchange reactions to remove Cs+ and Sr2+ compete with the reactions with other cations in the water sources. Since the groundwater and contaminated water have low concentrations of metal cations, the influence of competitive ion exchange reactions with protons (H+) is relatively large in the removal of Cs+ and Sr2+ from the water. In this paper, the H+/Na+ ion exchange property of the aqueous solution-CST system was evaluated. Results of batch tests were used to draw the isotherm and Kielland plot for the H+/Na+ ion exchange. The thermodynamic equilibrium constant K and the standard Gibbs energy ΔG 0 of the H+/Na+ ion exchange reaction were evaluated from the Kielland plot. CST exhibited high H+ selectivity in the H+/Na+ ion exchange reaction. The values of K and ΔG 0 were determined to be 7.3 × 104 and − 28 kJ mol−1, respectively. The selectivity of CST for H+ decreased with increasing H+ concentration on the ion exchange sites in CST.

Research on the Application of Multimedia Image Processing Technology in Sports Sociology Education

In order to cope with sports events, it is difficult for cameras to accurately extract exciting moments during the competition. This article constructs a multimedia information system for sports sociology education. In terms of methodology, low-density architectures are used to measure and encode sparse signals, and the signal is reconstructed at the receiving end. By calculating the marginal probability distribution of each variable node, the reconstructed image is obtained. The experimental results show that this method performs well in detecting lens mutations and gradients, with a higher recall rate than other algorithms. The accuracy, recall rate, and F-value indicators have significantly improved, reaching 6.328%, 4.27%, and 6.012%, respectively. This method is superior to existing game shot extraction methods and lays the foundation for further detecting exciting events in sports competitions. In summary, this study has important guiding significance for the application of multimedia image processing technology in the field of sports sociology education.

Investigation of the Potential of Repurposing Medium-Density Fiberboard Waste as an Adsorbent for Heavy Metal Ion Removal.

Medium-density fiberboard (MDF) waste generation has increased steadily over the past decades, and therefore, the investigation of novel methods to recycle this waste is very important. The potential of repurposing MDF waste as an adsorbent for the treatment of Cd(II), Cu(II), Pb(II), and Zn(II) ions in water was investigated using MDF offcuts. The highest adsorption potential in single-metal ion solution systems was observed for Pb(II) ions. The experimental data of Pb(II) ions fit well with the Freundlich isotherm and pseudo-second-order kinetic models. Complexation and electrostatic interactions were identified as the adsorption mechanisms. The adsorption behavior of multi-metal ion adsorption systems was investigated by introducing Cd(II) ions as a competitive metal ion. The presence of the Cd(II) ions reduced the adsorption potential of Pb(II) ions, yet the preference for the Pb(II) ions remained. Regeneration studies were performed by using 0.1 M HCl as a regeneration agent for both systems. Even though a significant amount of adsorbed metal ions were recovered, the adsorption potential of the MDF was reduced in the subsequent adsorption cycles. Based on these results, MDF fines have the potential to be used as an economical adsorbent for remediation of wastewater containing heavy metal ions.

Competitive sequestration behavior and mechanism of Cd2+, Pb2+and Ni2+ ions from single, binary and ternary metal laden solution by Hevea brasiliensis wood sawdust (HBS)

HeveaBrasiliensis wood sawdust (HBS), a lignocellulosic material, was employed for the eradication of Cd(II), Pb(II), and Ni(II) from synthetic single and multi-metalsystem. In the realm of multimetal adsorption, HBS exhibited the most substantial adsorption capacities for heavy metals, in the order: Pb(II) > Cd(II) > Ni(II). Experiments involving batch process were carried out to explore the rolesofpH, contact duration, HBS quantity, and preliminary metal concentrations on the adsorption capacity. Optimal conditions for biosorption of metal ions were determined as pH 5.0, dosage of 7 gL−1, and an equilibrium time of 90 min. The pseudo-second-order kinetics andLangmuirisotherm had a favorable alignment with the biosorption of all individual metal ions. Adsorption capacity was 8.45, 13.01 and 6.04 mg g− 1 for Cd, Pb and Ni respectively in single metal system. In binary and ternary system the capacity and adsorption percentages decreases significantly due the presence of competitive metal ions. HBS demonstrated effectiveness in treating real wastewater containing Cd2+, Pb2+and Ni2+ ionsin both single and mixed metal solutions, highlighting the necessity of thoroughly considering the impact of competitive adsorption. SEM with EDS results indicated single metal fixing in a multi-ion solution followed complex mechanisms. The surface area and functional group studies were conducted utilizing BET and a FTIR Spectrometer. Electrostatic attraction and complexation mechanisms were identified as responsible factor for capturing metal ions to the active surfaces of the bio sorbent. Cost analysis reflected the adsorbent cost was $0.021 per liter of mixed contaminated ternary effluent (30 mg L−1).

Synthesis and Characterization of Silver-Modified Nanoporous Silica Materials for Enhanced Iodine Removal.

In aquatic environments, the presence of iodine species, including radioactive isotopes like 129I and I2, poses significant environmental and health concerns. Iodine can enter water resources from various sources, including nuclear accidents, medical procedures, and natural occurrences. To address this issue, the use of natural occurring nanoporous minerals, such as zeolitic materials, for iodine removal will be explored. This study focuses on the adsorption of iodine by silver-modified zeolites (13X-Ag, 5A-Ag, Chabazite-Ag, and Clinoptilolite-Ag) and evaluates their performance under different conditions. All materials were characterized using scanning electron microscopey (SEM), energy-dispersive X-ray spectroscopy (EDS), powdered X-ray diffraction (P-XRD), Fourier-transform infrared spectrometry (FTIR), and nitrogen adsorption studies. The results indicate that Chabazite-Ag exhibited the highest iodine adsorption capacity, with an impressive 769 mg/g, making it a viable option for iodine removal applications. 13X-Ag and 5A-Ag also demonstrated substantial adsorption capacities of 714 mg/g and 556 mg/g, respectively, though their behavior varied according to different models. In contrast, Clinoptilolite-Ag exhibited strong pH-dependent behavior, rendering it less suitable for neutral to slightly acidic conditions. Furthermore, this study explored the impact of ionic strength on iodine adsorption, revealing that Chabazite-Ag is efficient in low-salinity environments with an iodine adsorption capacity of 51.80 mg/g but less effective in saline conditions. 5A-Ag proved to be a versatile option for various water treatments, maintaining its iodine adsorption capacity across different salinity levels. In contrast, Clinoptilolite-Ag exhibited high sensitivity to ionic competition, virtually losing its iodine adsorption ability at a NaCl concentration of 0.1 M. Kinetic studies indicated that the pseudo-second-order model best describes the adsorption process, suggesting chemisorption mechanisms dominate iodine removal. Chabazite-Ag exhibited the highest initial adsorption rate with a k2 value of 0.002 mg g-1 h-1, emphasizing its superior adsorption capabilities. Chabazite and Clinoptilolite, naturally occurring minerals, provide eco-friendly solutions for iodine adsorption. Chabazite superior iodine removal highlights its value in critical applications and its potential for addressing pressing environmental challenges.

Mathematical kinetic and thermodynamic study of adsorption of competitor ion as calcium II, magnesium II and sodium I on alkaline soil using batch method

Mathematical kinetic and thermodynamic study of adsorption of competitor ion as calcium II, magnesium II and sodium I on alkaline soil using batch method

ENGLISH TEACHERS’ READINESS IN DESIGNING LESSON PLAN BASED ON CURRICULUM MERDEKA AT VOCATIONAL SCHOOL NUMBER 1 JAMBI

This research, conducted by Kharisma Nur Azizah, explores the readiness of English teachers at SMKN 1 Kota Jambi in designing lesson plans based on the "Curriculum Merdeka." The study aims to identify the preparations and challenges faced by teachers in supporting their readiness for the 10th-grade lesson plans under this new curriculum framework. Utilizing a qualitative case study approach, the research collected data through interviews. The findings reveal several key aspects of readiness and challenges for English teachers. Readiness includes cognitive aspects such as the importance of lesson plan design, understanding the independent curriculum, using media resources to support lesson plan creation, and the ability to compile and evaluate lesson plans effectively. Physical readiness (energy and health), psychological readiness (interest and motivation), and the availability of supporting facilities and infrastructure are also critical components. The study found that the curriculum is both flexible and complex. Teachers utilize various media sources like ESP, TOEIC, the Merdeka teaching platform, and YouTube to prepare lesson plans based on major department profiles and determine competency (CP), topic (TP), and lesson activity plans (ATP). Physical readiness in designing lesson plans requires an intensive two-week period, while psychological readiness helps increase knowledge and update teaching experiences to meet student needs effectively.Challenges include time management and aligning lesson plans with diagnostic assessments of student characteristics to ensure they meet the standards of the Curriculum Merdeka.

Analysis of Brand Positioning in Online Course Companies to Change Consumption Patterns—A Case Study in the Personal Wellbeing Sector

This article examines the communication and marketing requirements of a prospective business enterprise that specializes in offering online courses focusing on psychology, personal growth and professional development to change patterns of educational production and consumption. The objective of this research is to analyse the necessary brand positioning for this company to improve its visibility, attracting and retaining interested customers. Using a sequential and evidence-based methodology, this study analyses the precise business requirements to establish an optimal and competitive platform for professionals offering wellbeing courses. This involved analysing the characteristics and needs of the target audience—the professionals who would deliver the courses—and the audience who would enrol in the courses. In addition, we assessed the company’s environmental context, its strengths, weaknesses and unique selling points, as well as effective marketing and positioning strategies, and its direct competitors. We identified a growing interest in online training of courses that contribute to wellbeing. Among the target audience, preferences were diverse, with 58.1% leaning towards personal growth, 45.9% interested in meditation and 43.2% in psychology. Social media, particularly YouTube (52.7%), served as the main source of information for these courses. Criticisms focused mainly on issues such as poor visual and audio quality (20%), inadequate structuring of content (30%) and perceived boredom (23.6%). Addressing these preferences through multilingual translation, niche targeting, diverse course offerings, flexible pricing and membership options can effectively cater to diverse customer segments. The findings emphasise the importance of prioritising audiovisual quality and personalised learning experiences to foster audience loyalty.

Update on Rehabilitation Strategies for Swimmers' Shoulder: A Narrative Review

AbstractSwimmers' shoulder is one of the common overuse injuries having multifactorial causes with a gradual onset. Swimmers' experience pain in the pull-through phase, during the mid-stroke wherein the arm is maximally internally rotated and adducted. This occurs due to a significant amount of force generated by the pectorals, latissimus dorsi, subscapularis, serratus anterior, rhomboids, and supraspinatus for this movement. The repetitive use of shoulder muscles during the swim strokes predisposes it to overuse injuries among which shoulder impingement is common. It hinders participation of athletes in competitive events and reduces the efficiency of the swim performance. This review aims to provide a consolidated overview and identify various rehabilitation strategies and exercise programs for swimmers' shoulder. A thorough search was done on PubMed, ScienceDirect, Web of Science, Cochrane, CINAHL, and Clinical Key to find relevant articles in relation to the rehabilitation strategies available for swimmers' shoulder. Overall, this review suggests that aquatic concentric-eccentric exercise, Kinesio taping, land-based strengthening exercises, and rhythmic stabilization exercises significantly improve pain and functional activity in individuals with swimmers' shoulder.

The impact of non-HDL-C level on major adverse cardiovascular and cerebrovascular events and all-cause mortality after revascularization

Objective: To investigate the impact of non-high-density lipoprotein cholesterol (non-HDL-C) level on major adverse cardiovascular and cerebrovascular events (MACCE) and all-cause mortality in the Kailuan Study cohort undergoing revascularization. Methods: This is a prospective cohort study, with participants from the Kailuan Study cohort who participated in physical examinations from 2006 to 2020 and received revascularization therapy for the first time. According to the level of non-HDL-C, the study subjects were divided into 3 groups:<2.6 mmol/L group, 2.6-<3.4 mmol/L group, and≥3.4 mmol/L group. Annual follow-up was performed, and the endpoint events were MACCE and all-cause mortality. Cox proportional regression model was implemented to estimate the impact on MACCE and all-cause mortality associated with the different non-HDL-C groups. The partial distributed risk model was used to analyze the impact of different non-HDL-C levels on MACCE event subtypes, and death was regarded as a competitive event. The restricted cubic spline regression model was used to explore the dose-response relationship between non-HDL-C level and all-cause mortality, MACCE and its subtypes. Results: A total of 2 252 subjects were enrolled in the study, including 2 019 males (89.65%), aged (62.8±8.3) years, the follow-up time was 5.72 (3.18, 8.46) years. There were 384 cases(17.05%) of MACCE and 157 cases(6.97%) of all-cause mortality. Compared with patients with non-HDL-C≥3.4 mmol/L, patients with non-HDL-C<2.6 mmol/L were associated with a 38% reduced risk of MACCE after revascularization [HR=0.62(95%CI: 0.48-0.80)]. Every 1 mmol/L decrease in non-HDL-C was associated with a 20% reduction in the risk of MACCE [HR=0.80(95%CI: 0.73-0.88)]. The results of restricted cubic spline also showed that non-HDL-C levels after revascularization therapy were positively correlated with MACCE events (overall association P<0.001, non-linear association P=0.808). For all-cause mortality, compared to the non-HDL-C≥3.4 mmol/L group, the HR for all-cause mortality after revascularization in non-HDL-C<2.6 mmol/L group was 0.67(95%CI: 0.46-1.01). Every 1 mmol/L decrease in non-HDL-C was associated with a 15% reduction in the risk of all-cause mortality [HR=0.85(95%CI: 0.73-0.99)]. The restricted cubic spline results showed a linear association between non-HDL-C levels after revascularization therapy and the risk of all-cause mortality (overall association P=0.039, non-linear association P=0.174). Conclusion: The decrease in non-HDL-C levels after revascularization were significantly associated with a reduced risk of MACCE and all-cause mortality.

Hydrothermal pre-anchoring and in-situ preparation of Prussian blue analogue-polymeric carbon nitride nanorods hybrid for robust and efficient cesium adsorption

Prussian blue analogues (PBAs) are recognized as effective and selective adsorbents for Cs+, however, they suffered from unsatisfactory post-separation performance and inevitable dissolution loss arising from the small size and inferior water instability. In this study, Zn-PBA nanoparticles were integrated onto polymeric carbon nitride (PCN) nanorods to form PBA-PCN hybrid via hydrothermal pre-anchoring and in-situ growth method. The robust and amino-rich PCN played dual roles in securely anchoring the Zn2+ precursor and attracting Cs+ to the surface. Benefiting from the effects of PCN and in-situ generated PBA, PBA-PCN exhibited boosting post-separation performance and water stability in acid and alkaline solutions, which was attractive in different application scenarios. Moreover, PBA-PCN has been demonstrated to be with high adsorption capacity of 376.41 mg/g and favorable selectivity even in the presence of excessive competitive ions. The experimental results and DFT calculations suggested the adsorption mechanism involving strong incorporation/ion exchange and weak electrostatic attraction. The remarkable adsorption performance along with the satisfactory post-separation performance and water stability made it a promising candidate in Cs+ removal and separation.

Third-generation posterior-stabilised cemented system for total knee arthroplasty: Survivorship and outcomes after 20-year follow-up.

Total knee arthroplasty is a common procedure due to increased life expectancy and ageing populations, necessitating implants with long-term efficacy. After some initial designs, the third-generation modular posterior-stabilised NexGen® prosthesis aimed to enhance kinematics and reduce complications. This study evaluates the long-term outcomes, survivorship, revision rates and complications of this implant. With promising results observed up to 15 years in previous studies, this investigation aims to assess the implant's performance over extended follow-up periods, aiding in optimal implant selection for improved patient outcomes. We carried out a retrospective study on 263 total knee arthroplasties performed in our centre between 1998 and 2002. Statistical analysis of complications was performed and study of survival using the Kaplan-Meier method and competing risk analysis were calculated. Description of reinterventions and complications were also included. Results show a 20-year prosthesis survival rate of 90.8% for revision due to any reason, with an estimated survival of 92.3% considering competitive events. Estimated survivorship at 20 years is 98% for aseptic loosening as the end point, and an estimation of 98.80% considering competitive events. Twenty revisions were performed, with 10 cases due to infection and 10 for noninfectious reasons and three of them due to aseptic loosening. Radiographic analysis revealed radiolucent lines, but no clinical evidence of loosening was observed in these cases. This study offers survivorship data from longer follow-up periods, what is difficult to find in the reported literature and showed excellent results of this implant in terms of survivorship and low rates of revision in our cohort. Level IV.

A reversible fluorescent chemosensor based on a naphthalene dyad for Pb(II) ions: Applications in food, water, and bio-imaging

Lead (Pb2+) ions, among heavy toxic metals, are extensively distributed and bioaccumulate in food chains, prompting researchers to monitor their levels in water and biosystems. Consequently, aiming to protect the environment and human health, this study synthesizes a straightforward naphthalene-naphthalene dyad-based "turn-on" fluorescent chemosensor (S) tailored for detecting Pb2+ ions. This selective response to Pb2+ ions over other competing metal ions is characterized by hypsochromic changes in fluorescence enhancement resulting from an intramolecular charge transfer (ICT) process from -OH group (donor) to the naphthyl ring (acceptor) following the complexation of S-Pb2+. Moreover, cross-contamination titration for probe S was conducted in the presence of various distinct competitive metal ions. By employing Job's plot and B-H plot, the complicated stoichiometry (1:2) and association constant (Ka = 9.45×104 M−1) of S-Pb2+ were studied. The probe's interaction with Pb2+ is studied using spectroscopic measurements and DFT calculations. The probe demonstrated exceptional selectivity and sensitivity, achieving a limit of detection (LOD) value of 12.50×10−6 M for Pb2+ in a buffered THF:H2O (50:50, v:v) medium. The applicability of chemosensor S spans across various water, food, and E. coli samples, indicating its potential in monitoring and managing Pb2+ toxicity in wastewater and biosystems.

Business Model Canvas and Competition to Understand Exploitation of Cybersecurity Project Results

The European Commission (EC) has lately funded 22 different cybersecurity projects (European Commission, 2024), and the European Union (EU) expects a return for the investment and requires these projects to demonstrate efficient exploitation activities that emphasize their influence on the European economy. The Business Model Canvas (BMC) is a tool to actively guide discussion and processes that evolve and adapt based on their environments. Yet, the tool does not address the competition on the marketplace. For this reason, this study introduces the ‘Business Model Canvas and Competition’ (BMC&amp;C) by including the element of competence to the traditional BMC and examines its usefulness to understand the relations between an organisation and its competitive environment. The data collection method for this study was action research through actively participating in the exploitation workshops activities and reading what materials were produced. The BMC by Osterwalder and Pigneur (2011) consists of the nine building blocks. This study modified the BMC as a framework of analysis by adding tenth building block ‘Competition’ (&amp;C) that acknowledges that an organization is not alone but is part of a market where it encounters competition by active direct competitors and by indirect alternative ways to achieve similar results. This tenth building block ‘Competition’ (&amp;C) was deemed important to better understand what possible competitive advantages and challenges the analysed assets of the ECHO project may encounter. The BMC&amp;C was used in ECHO exploitation workshop that addressed the ECHO asset ECHO Early Warning System (E-EWS). The E-EWS asset BMC&amp;C example show that users found the BMC&amp;C easy to use. As the &amp;C was added as a tenth element or building block the use of the tool was familiar to anyone who had used a conventional BMC. Those who had no prior experience of the BMC tool received guidance from the more experienced users. The workshops included active and co-creative discussions that shaped the outcomes of the BMC&amp;C for each individual ECHO asset. The results of this study indicate that the BMC&amp;C can be a valuable tool to assess how an organisation that is active in a marketplace may need to take their competition into account. The contribution of this study to practice is a deeper understanding of competition and market on a very practical case level, while its contribution to theory is the accumulation of data from multiple cases.

A novel and recyclable silica gel-modified biochar to remove cadmium from wastewater: Model application and mechanism exploration

Water pollution caused by heavy metals is a major environmental problem, threatening water production, food safety, and human health. Cadmium (Cd) pollution is particularly serious because of food-chain biomagnification at toxic concentrations. Modified biochar is promising for heavy metal removal; however, efficient adsorbents for Cd removal are lacking. In the present study, a novel adsorbent, silica gel-modified biochar (SGB), was prepared and applied to treat sewage polluted by Cd. Through the batch adsorption experiments, it is known that SGB possessed outstanding Cd removal ability and recycleability. Furthermore, the adsorption behavior and mechanisms were analyzed by the application of kinetic and isotherm models. The maximum Cd2+ adsorption capacity of SGB was 38.08 mg g−1, and after five recycling processes, the Cd2+ removal rate was still 86.89 %. When the pH of the solution was 7.0, SGB showed the strongest Cd2+ adsorption capacity (29.06 mg g−1). When competitive ions existed, biochar also had high Cd removal efficiency, although the effect of Pb2+ was greater than those of Cu2+ and Zn2+, indicating that SGB was applicable to complex polluted water. Additionally, the main Cd2+ adsorption mechanisms by SGB were electrostatic interactions, π-π interactions, complexation, and co-precipitation. These results showed that SGB can effectively treat Cd-contaminated wastewater as a new adsorbent.

Highly selective recovery of rare earth elements from mining wastewater using phyto-synthesized biochar dispersed iron nanoparticles

Recovery of rare earth elements (REEs) from secondary sources such as mining wastewater has attracted much recent attention due to the rising global demand for REEs and the need to environmentally protect potentially contaminated mine sites. One significant issue it that most adsorbents proposed for removal and/or recovery of REEs are not generally selective for REEs. In this study, biochar dispersed iron nanoparticles synthesized using a plant extract (BC-FeNPs) were successfully used for the selective recovery of REEs from mining wastewater, where the Kd values were Nd(III) (918 mL∙g−1), Eu(III) (1253 mL∙g−1), Tb(III) (1119 mL∙g−1), Dy(III) (1032 mL∙g−1), Lu(III) (1898 mL∙g−1), compared to only 23.9 mL∙g−1 for Zn(II). The maximum adsorption efficiency of REEs for the composite was higher than the constituent parts being 88.4 % for BC-FeNPs, but only 8.72 % for biochar and 82.4 % for FeNPs, respectively. FTIR, XPS and Zeta potential analysis suggested that the observed selective adsorption of REEs, involved interactions of REEs with O and N, as well as ion-exchange with H+ from the biochar and capping layer, as well as electrostatic interactions. The desorption efficiency of bound REEs from BC-FeNPs was > 85 % when using acetic acid, and was attributed to efficient competitive ion exchange. Pearson correlation analysis further demonstrated that the adsorption mechanism included ion complexation, ion exchange and electrostatic adsorption, while the desorption mechanism was mainly via ion exchange. Overall, BC-FeNPs has significant potential to practically recover REEs from mining wastewater having demonstrated excellent reusability after five adsorption–desorption cycles.