Direct Observation of Photon Induced Giant Band Renormalization in 2D PdSe2 Dichalcogenide by Transient Absorption Spectroscopy.

Insight into fundamental light-matter interaction as well as underlying photo-physical processes is crucial for the development of novel optoelectronic devices. Palladium diselenide (PdSe2 ), an important representative of emerging 2D noble metal dichalcogenides, has gain considerable attention owing to its unique optical, physical, and chemical properties. In this study, 2D PdSe2 nanosheets (NSs) are prepared using the liquid-phase exfoliation method. A broadband carrier relaxation dynamics from visible to near-infrared bands are revealed using a time-resolved transient absorption spectrometer, giving results that indicate band filling and bandgap renormalization (BGR) effects in the 2D PdSe2 NSs. The observed blue-shift of the transient absorption spectra at the primary stage and the subsequent red-shift can be ascribed to this BGR effect. These findings reveal the many-body character of the 2D TMDs material and may hold keys for applications in the field of optoelectronics and ultrafast photonics.

A Targeted Review of Current Progress, Challenges and Future Perspective of g-C3 N4 based Hybrid Photocatalyst Toward Multidimensional Applications.

The increasing demand for searching highly efficient and robust technologies in the context of sustainable energy production totally rely onto the cost-effective energy efficient production technologies. Solar power technology in this regard will perceived to be extensively employed in a variety of ways in the future ahead, in terms of the combustion of petroleum-based pollutants, CO2 reduction, heterogeneous photocatalysis, as well as the formation of unlimited and sustainable hydrogen gas production. Semiconductor-based photocatalysis is regarded as potentially sustainable solution in this context. g-C3 N4 is classified as non-metallic semiconductor to overcome this energy demand and enviromental challenges, because of its superior electronic configuration, which has a median band energy of around 2.7 eV, strong photocatalytic stability, and higher light performance. The photocatalytic performance of g-C3 N4 is perceived to be inadequate, owing to its small surface area along with high rate of charge recombination. However, various synthetic strategies were applied in order to incorporate g-C3 N4 with different guest materials to increase photocatalytic performance. After these fabrication approaches, the photocatalytic activity was enhanced owing to generation of photoinduced electrons and holes, by improving light absorption ability, and boosting surface area, which provides more space for photocatalytic reaction. In this review, various metals, non-metals, metals oxide, sulfides, and ferrites have been integrated with g-C3 N4 to form mono, bimetallic, heterojunction, Z-scheme, and S-scheme-based materials for boosting performance. Also, different varieties of g-C3 N4 were utilized for different aspects of photocatalytic application i. e., water reduction, water oxidation, CO2 reduction, and photodegradation of dye pollutants, etc. As a consequence, we have assembled a summary of the latest g-C3 N4 based materials, their uses in solar energy adaption, and proper management of the environment. This research will further well explain the detail of the mechanism of all these photocatalytic processes for the next steps, as well as the age number of new insights in order to overcome the current challenges.

Recent Advancement of the Current Aspects of g-C3 N4 for its Photocatalytic Applications in Sustainable Energy System.

Being one of the foremost enticing and intriguing innovations, heterogeneous photocatalysis has also been used to effectively gather, transform, and conserve sustainable sun's radiation for the production of efficient and clean fossil energy as well as a wide range of ecological implications. The generation of solar fuel-based water splitting and CO2 photoreduction is excellent for generating alternative resources and reducing global warming. Developing an inexpensive photocatalyst can effectively split water into hydrogen (H2 ), oxygen (O2 ) sources, and carbon dioxide (CO2 ) into fuel sources, which is a crucial problem in photocatalysis. The metal-free g-C3 N4 photocatalyst has a high solar fuel generation potential. This review covers the most recent advancements in g-C3 N4 preparation, including innovative design concepts and new synthesis methods, and novel ideas for expanding the light absorption of pure g-C3 N4 for photocatalytic application. Similarly, the main issue concerning research and prospects in photocatalysts based g-C3 N4 was also discussed. The current dissertation provides an overview of comprehensive understanding of the exploitation of the extraordinary systemic and characteristics, as well as the fabrication processes and uses of g-C3 N4 .

CdS@CdSe Core/Shell Quantum Dots for Highly Improved Self-Powered Photodetection Performance.

Uniform, well-defined cadmium sulfide@cadmium selenide core/shell quantum dots (CdS@CdSe QDs) were, for the first time, successfully synthesized by a solvothermal method and chemical bath growth for photoelectrochemical activities. The as-synthesized CdS@CdSe QDs not only exhibit superior self-powered photoresponse behavior and excellent stability under ambient conditions but also display significantly improved current densities and photoresponsivity compared to those of individual CdS QDs or CdSe QDs, mainly due to the built-in electric field, and thus have great potential in the fields of renewable energy and renewable energy consumption for carbon neutrality target achievement.

Engine performance and emission characteristics of palm biodiesel blends with graphene oxide nanoplatelets and dimethyl carbonate additives.

This study investigated the engine performance and emission characteristics of biodiesel blends with combined Graphene oxide nanoplatelets (GNPs) and 10% v/v dimethyl carbonate (DMC) as fuel additives as well as analysed the tribological characteristics of those blends. 10% by volume DMC was mixed with 30% palm oil biodiesel blends with diesel. Three different concentrations (40, 80 and 120 ppm) of GNPs were added to these blends via the ultrasonication process to prepare the nanofuels. Sodium dodecyl sulphate (SDS) surfactant was added to improve the stability of these blends. GNPs were characterised using Scanning Electron Microscope (SEM) and Fourier Transform Infrared (FTIR), while the viscosity of nanofuels was investigated by rheometer. UV-spectrometry was used to determine the stability of these nanoplatelets. A ratio of 1:4 GNP: SDS was found to produce maximum stability in biodiesel. Performance and emissions characteristics of these nanofuels have been investigated in a four-stroke compression ignition engine. The maximum reduction in BSFC of 5.05% and the maximum BTE of 22.80% was for B30GNP40DMC10 compared to all other tested blends. A reduction in HC (25%) and CO (4.41%) were observed for B30DMC10, while a reduction in NOx of 3.65% was observed for B30GNP40DMC10. The diesel-biodiesel fuel blends with the addition of GNP exhibited a promising reduction in the average coefficient of friction 15.05%, 8.68% and 3.61% for 120, 80 and 40 ppm concentrations compared to B30. Thus, combined GNP and DMC showed excellent potential for utilisation in diesel engine operation.

A New Benchmark of Charges Storage in Single-Layer Organic Light-Emitting Diodes Based on Electrical and Optical Characteristics.

The storage of charges in organic light-emitting diodes (OLEDs) has drawn much attention for its damage to device performance as well as the loss to carriers. Thus, it is essential to address the issue and do further investigation. The traditional approach to storage analysis is mainly based on transient measurement since it is sensitive to transient instead of steady signal. In this paper, we proposed a new benchmark to investigate the single-layer OLEDs capable of stored charges with poly (methyl methacrylate) (PMMA), which is just based on electrical and optical characteristics. Since the stored charges contribute both to luminance and current of the devices with PMMA, the area between them can be taken as a benchmark and evaluated the storage of charges. In our experiment, the areas of 4 nm, 6 nm, 8 nm, and 10 nm PMMA devices are 0.348, 0.554, 0.808, and 0.894, respectively, indicating a higher capability of storage in thicker PMMA. It is exactly in line with the results taken from transient electroluminescence (EL) measurement. Thus, this new benchmark is practical and provides a more accessible approach to investigate the storage of charges in OLEDs.

Optical Capacitance/Conductance-Voltage Characteristics of Stored Charges in Organic Light-Emitting Diodes.

In this paper, capacitance/conductance-voltage characteristics (C/G-V) under illumination was achieved to investigate the dynamic mechanism of stored charges in OLEDs with a structure of ITO/ PEDOT:PSS/PMMA/Alq3/Al. For all devices, at least two peaks presented in the optical capacitance-voltage curve. Compared to curves of devices under dark, the first peak increased remarkably with a deviation to Vbi, which can be explained in the form of stored charges combined with the optical conductance characteristics. It was also found that a great decrease in capacitance is followed by the collapse of the first peak with PMMA thickness increased. It can account for the presence of interfacial charges, which is proved further by the conductance curves. To the device with 10 nm PMMA, a third peak took place in optical capacitance and it was due to the storage of electrons by PMMA. Also, the first capacitance peak enhanced approximate linearly as the illumination power increased, which can verify the contribution of the stored charges. Additionally, it shows the potential for the stored charges in optical detections.

Graphene in Photocatalysis: A Review.

In recent years, heterogeneous photocatalysis has received much research interest because of its powerful potential applications in tackling many important energy and environmental challenges at a global level in an economically sustainable manner. Due to their unique optical, electrical, and physicochemical properties, various 2D graphene nanosheets-supported semiconductor composite photocatalysts have been widely constructed and applied in different photocatalytic fields. In this review, fundamental mechanisms of heterogeneous photocatalysis, including thermodynamic and kinetics requirements, are first systematically summarized. Then, the photocatalysis-related properties of graphene and its derivatives, and design rules and synthesis methods of graphene-based composites are highlighted. Importantly, different design strategies, including doping and sensitization of semiconductors by graphene, improving electrical conductivity of graphene, increasing eloectrocatalytic active sites on graphene, strengthening interface coupling between semiconductors and graphene, fabricating micro/nano architectures, constructing multi-junction nanocomposites, enhancing photostability of semiconductors, and utilizing the synergistic effect of various modification strategies, are thoroughly summarized. The important applications including photocatalytic pollutant degradation, H2 production, and CO2 reduction are also addressed. Through reviewing the significant advances on this topic, it may provide new opportunities for designing highly efficient 2D graphene-based photocatalysts for various applications in photocatalysis and other fields, such as solar cells, thermal catalysis, separation, and purification.

Nickel Cobaltite Nanostructures for Photoelectric and Catalytic Applications.

Bimetallic oxide nickel cobaltite (NiCo2 O4 ) shows extensive potential for innovative photoelectronic and energetic materials owing to their distinctive physical and chemical properties. In this review, representative fabrications and applications of NiCo2 O4 nanostructures are outlined for photoelectronic conversion, catalysis, and energy storage, aiming to promote the development of NiCo2 O4 nanomaterials in these fields through an analysis and comparison of their diverse nanostructures. Firstly, a brief introduction of the spinel structures, properties, and morphologies of NiCo2 O4 nanomaterials are presented. Then, the advanced progress of NiCo2 O4 nanomaterials for both photoelectronic conversion and energy fields is summarized including such examples as solar cells, electrocatalysis, and lithium ion batteries. Finally, further prospects and promising developments of NiCo2 O4 nanomaterials in these significant fields are proposed.

Composition of soil microbiome along elevation gradients in southwestern highlands of Saudi Arabia.

BACKGROUND: Saudi Arabia is mostly barren except the southwestern highlands that are susceptible to environmental changes, a hotspot for biodiversity, but poorly studied for microbial diversity and composition. In this study, 454-pyrosequencing of 16S rRNA gene hypervariable region V6 was used to analyze soil bacterial community along elevation gradients of the southwestern highlands. RESULTS: In general, lower percentage of total soil organic matter (SOM) and nitrogen were detected in the analyzed soil samples. Total 33 different phyla were identified across the samples, including dominant phyla Proteobacteria, Actinobacteria and Acidobacteria. Representative OTUs were grouped into 329 and 508 different taxa at family and genus level taxonomic classification, respectively. The identified OTUs unique to each sample were very low irrespective of the altitude. Jackknifed principal coordinates analysis (PCoA) revealed, overall differences in the bacterial community were more related to the quantity of specific OTUs than to their diversity among the studied samples. CONCLUSIONS: Bacterial diversity and soil physicochemical properties did not show consistent changes along the elevation gradients. The large number of OTUs shared between the studied samples suggest the presence of a core soil bacterial community in the southwestern highlands of Saudi Arabia.

Johanson-Blizzard syndrome caused by novel UBR1 mutation in four Saudi patients.

Johanson-Blizzard syndrome (JBS) is a rare genetic disorder caused by Ubiquitin Protein Ligase E3 Component N-Recognin1 (UBR1) gene mutations. It is characterized by exocrine pancreatic insufficiency, craniofacial deformities, sensorineural hearing loss, and a broad variety of intellectual disabilities. The aim of our study is to report four pediatric cases (three of which are siblings, and the fourth patient is unrelated) that presented some features of JBS. The cases have been confirmed by genetic testing to have mutations in the UBR1 gene. This case series study was conducted retrospectively, giving a detailed description of the demographic and clinical information of these four cases, and reflecting our experience with this subset of patients. All these cases have been treated at the King Faisal Specialist Hospital and Research Center, Jeddah, Saudi Arabia, and were identified by their clinical and laboratory markers that favor JBS. A novel homozygous missense mutation c.2075 T > C (p. lle692Thr) in exon 18 (UBR1: NM_174916.3) was identified and confirmed by Sanger sequencing in all our cases outlined in this paper. These presented cases illustrate the phenotypic variability and complexity of JBS and the importance of physical examination to reach a diagnosis. The identified novel mutation in this study broadens the spectrum of UBR1 mutations that contribute to JBS.

Determinants of Parental Vaccine Hesitancy During the COVID-19 Era in Saudi Arabia: A Cross-Sectional Survey.

Background Despite the success of childhood vaccination in reducing vaccine-preventable diseases (VPDs), vaccine hesitancy remains a significant challenge in several countries, such as Saudi Arabia, both during and beyond the COVID-19 era. Furthermore, the pandemic may have impacted vaccine hesitancy trends, potentially affecting parents' intentions to adhere to scheduled childhood vaccination programs. Aim This article aims to assess the extent of parents' hesitancy toward childhood vaccination, determine if it increased or decreased due to the COVID-19 pandemic, highlight the factors and determinants that influenced this hesitancy, whether positively or negatively, during the COVID-19 era, and estimate the acceptance of COVID-19 vaccination in relation to the acceptance of scheduled childhood vaccination. Methods A cross-sectional study was conducted in Saudi Arabia through a snowball sampling technique. Data were collected between September 2022 and October 2022 using an online survey using Google Forms. The inclusion criteria were parents or guardians in Saudi Arabia with a child up to 18 years of age. Responses were analyzed using SPSS V25 (IBM Corp., Armonk, NY, US), with chi-square tests and logistic regression performed to compare hesitancy and vaccination status. Results Among the 1,209 parents and care providers who participated, the prevalence of parents' vaccine hesitancy was 374 (30.9%). The educational level of the parents was not significantly associated with hesitancy status (p 0.490). The most refused vaccine was Mpox (345; 28.5%), whereas the one that caused the most hesitancy was the COVID-19 vaccine (352; 29.1%). Regarding the parents' concerns, the main reason for their hesitancy was the influence of their negative perceptions from social media content, including false or misleading information and negative allegations about vaccines, reported by 449 (18.98%) of the participants. Logistic regression analysis indicated that negative social media perceptions significantly increased the likelihood of vaccine hesitancy (OR = 2.15, 95% CI = 1.78-2.60, p < 0.001). Conclusion Our study highlights the prevalence of parental vaccine hesitancy during the COVID-19 era; the most significant hesitancy was observed toward the COVID-19 vaccine, and the mpox vaccine was the most rejected. Negative social media was the main reason for parental hesitancy; public health efforts should focus on providing accurate and easily accessible information through educational campaigns on social media and other platforms.

Defects in lead halide perovskite light-emitting diodes under electric field: from behavior to passivation strategies.

Lead halide perovskites (LHPs) are emerging semiconductor materials for light-emitting diodes (LEDs) owing to their unique structure and superior optoelectronic properties. However, defects that initiate degradation of LHPs through external stimuli and prompt internal ion migration at the interfaces remain a significant challenge. The electric field (EF), which is a fundamental driving force in LED operation, complicates the role of these defects in the physical and chemical properties of LHPs. A deeper understanding of EF-induced defect behavior is crucial for optimizing the LED performance. In this review, the origins and characterization of defects are explored, indicating the influence of EF-induced defect dynamics on LED performance and stability. A comprehensive overview of recent defect passivation approaches for LHP bulk films and nanocrystals (NCs) is also provided. Given the ubiquity of EF, a summary of the EF-induced defect behavior can enhance the performance of perovskite LEDs and related optoelectronic devices.

Differences and associations of metabolic and vitamin D status among patients with and without sub-clinical hypothyroid dysfunction.

BACKGROUND: Sub-clinical hypothyroid dysfunction, a relatively understudied disorder in the Kingdom of Saudi Arabia (KSA), has significant clinical implications if not properly monitored. Also from KSA, more than 50% of the population suffer from hypovitaminosis D (<50 nmol/l). In this cross-sectional case-control study, we described the differences and associations in the metabolic patterns of adult Saudis with and without hypothyroid dysfunction in relation to their vitamin D status, PTH, calcium and lipid profile. METHODS: A total of 94 consenting adult Saudis [52 controls (without subclinical hypothyroidism), 42 cases (previously diagnosed subjects)] were included in this cross-sectional study. Anthropometrics were obtained and fasting blood samples were taken for ascertaining lipid and thyroid profile, as well as measuring PTH, 25(OH) vitamin D and calcium. RESULTS: Cases had a significantly higher body mass index than the controls (p < 0.001). Circulating triglycerides was also significantly higher in cases than the controls (p = 0.001). A significant positive association between HDL-cholesterol and PTH (R = 0.56; p = 0.001), as well as a negative and modestly significant negative association between LDL-cholesterol and PTH (R = - 20.0; p = 0.04) were observed. FT3 was inversely associated with circulating 25 (OH) vitamin D (R = -0.25; p = 0.01). CONCLUSIONS: Patients with hypothyroid dysfunction possess several cardiometabolic risk factors that include obesity and dyslipidemia. The association between PTH and cholesterol levels as well as the inverse association between vitamin D status and FT3 needs to be reassessed prospectively on a larger scale to confirm these findings.

A Flexible Miniature Antenna for Body-Worn Devices: Design and Transmission Performance.

The last few years have seen a rapid increase in body-worn devices because these devices cover a broad spectrum of potential uses. Moreover, body-worn devices still require improvements in their flexibility, size, and weight that necessitate the development of flexible and miniature antennas. In this paper, we present a new flexible miniature antenna for body-worn devices. To ensure flexibility and comfort when the antenna is in contact with the human body, a substrate from natural rubber filled with TiO2 is developed. The miniaturization is achieved using the quadratic Koch curve. The antenna design, optimization, and characterization are performed on a human body model. The performance of the antenna is analyzed in two scenarios: (1) in- to on-body, and (2) on- to off-body wireless communications. The results show that the antenna realized the maximum telemetry range of more than 80 mm for in-body communications and more than 2 m for off-body communications. Moreover, the highest 10 g specific absorption rate value was 0.62 W/kg. These results, in addition to the antenna's compact dimensions (12 mm × 26 mm × 2.5 mm) and the low manufacturing price, make the proposed antenna an ideal candidate for health telemetry applications.

Giant condyloma acuminatum surgical management: a case report and literature review.

Introduction and importance: Condyloma acuminatum (CA) or genital warts, represents a rare sexually transmitted disease caused by the human papillomavirus. Infection occurs when host basal cells are exposed to viral infection through a damaged epithelial barrier, during sexual intercourse, or due to other minor skin abrasions. Giant condyloma acuminatum (GCA) has a higher rate of malignant transformation than CA. Case presentation: We are presenting a 44-year-old single gentleman known as a smoker, hepatitis B positive, vitiligo, and hypercholesteromia. He was an alcoholic and had multiple heterosexual relationships abroad. Referred from the dermatology clinic, complaining of genital warts that had increased in size for 10 years. Clinical discussion: CA management includes local applications like imiquimod and podophyllotoxin and clinician-administered treatments such as cryotherapy, surgical excision, electrosurgery, and CO2 laser therapy. Other options, such as interferon, radiotherapy, or chemotherapy, are available. The selection of therapy should be individualized and based upon consideration of the extent of the disease, patient preference, cost, adverse effects, treatment availability, and the response to previous treatments. Complete surgical excision is the treatment of choice for GCA. Conclusion: We present a patient with GCA in the perianal area that was surgically treated with an excellent outcome.

Room Temperature Synthesized TiO2 Nanoparticles for Two-Folds Enhanced Mechanical Properties of Unsaturated Polyester.

Using of nano-inclusion to reinforce polymeric materials has emerged as a potential technique to achieve an upper extreme of specific strength. Despite the significant improvement of mechanical properties via nano-reinforcements, the commercial application of such nano-composites is still restricted, due to high cost and unwanted aggregation of nanoparticles in the polymer matrix. To address these issues, here we proposed a scalable and economical synthesis of TiO2 at low temperatures, resulting in self-dispersed nanoparticles, without any surfactant. As lower energy is consumed in the synthesis and processing of such nanoparticles, so their facile gram-scale synthesis is possible. The defect-rich surface of such nanoparticles accommodates excessive dangling bonds, serving as a center for the functional groups on the surface. Functional surface enables high dispersion stability of room temperature synthesized TiO2 particles. With this motivation, we optimized the processing conditions and concentration of as-synthesized nano-particles for better mechanical properties of unsaturated polyester (UP) resin. The composite structure (UP-TiO2) showed nearly two folds higher tensile, flexural, and impact strength, with 4% content of nanoparticles. Characterization tools show that these better mechanical properties are attributed to a strong interface and superior dispersion of nanoparticles, which facilitate better stress distribution in the composite structure. In addition, the crack generation and propagation are restricted at a much smaller scale in nanocomposites, therefore significant improvement in mechanical properties was observed.

Toxoplasma and Toxocara seropositivity in juvenile idiopathic arthritis and its relation to disease activity and type of therapies.

Juvenile idiopathic arthritis (JIA) is the most frequently encountered autoimmune rheumatic disease in children. To our knowledge, this is the first study aimed to estimate the frequency of Toxoplasma gondii (T. gondii) and Toxocara seropositivity in JIA and assess its relation to the disease activity, IL-10 levels, and type of the received therapies. This study was conducted on 43 JIA patients and 50 cases as a control group. All participants were evaluated by disease activity score (JADAS-27), and the presence of specific IgG and IgM antibodies against T. gondii and IgG against Toxocara species using an enzyme-linked immunosorbent assay. IL-10 serum levels were measured using an ELISA kit. The results show that JIA patients have significantly higher seropositivity for anti-T. gondii IgG compared to control subjects (p = 0.02) and a non-significant difference for Toxocara seropositivity (p = 0.41). All participants were negative for IgM anti-Toxoplasma gondii. Demographic parameters did not significantly affect these seroprevalence frequencies (p > 0.05). IL-10 was significantly higher among JIA patients compared to controls (p = 0.007) and seropositive anti-T. gondii JIA exhibited significantly higher IL-10 levels compared to seronegative ones (p = 0.03). Seropositive anti-T. gondii IgG JIA patients had a significantly higher disease activity score (JADAS-27) than seronegative anti-T. gondii IgG cases (p = 0.02). There was a significant positive correlation between anti-T. gondii IgG and JADAS-27 score (p = 0.009). A significant association was detected between T. gondii infection and DMARDs including the biological therapies (p < 0.05). Overall, this study supports a possible association between T. gondii infection and JIA, IL-10, disease activity score, and DMARDs therapies. It is possible that IL-10 plays a role in the development of JIA and contributes to persistent asymptomatic infection with T. gondii in JIA patients. As a result, a recommendation for screening tests for T. gondii infection among JIA patients is crucial before and during commencing DMARDs therapies and closely monitoring early signs of infection.

Attitude of Self-Medication Among Pharmacy Students in King Abdulaziz University, Jeddah, Saudi Arabia: A Cross-Sectional Survey.

Background/purpose Self-medication is a public health concern because of the potential for medication overuse or abuse, as well as the physical, social, and psychological consequences. In Saudi Arabia, self-medication is common, especially among health science students. Inappropriate self-medication can cause several adverse effects, such as increasing the risk of medication abuse or delaying hospital appointments due to concealing specific symptoms with some medications. Therefore, our study aims to investigate and evaluate health science students' practices, awareness, and attitudes towards self-medication in the Faculty of Pharmacy at King Abdulaziz University, Jeddah, Saudi Arabia. Materials and methods A cross-sectional study was conducted using an online self-administered survey to measure the attitude, awareness, and prevalence of self-medication among pharmacy students at King Abdulaziz University in Jeddah, Saudi Arabia. Students in the pharmacy program from the first to the sixth year were invited to participate in the study from April 2019 to June 2019. Raosoft was used to compute the sample size (n = 235) with a 5% margin of error and a 95% confidence range. Results The factors associated with significant effects were an academic year (p = 0.001), smoking (p = 0.018), average sleeping time (p = 0.032), having any headache (p = 0.022), and their opinion about self-medication (p < 0.0001). Conclusion According to the study, the self-medication of analgesics is common among pharmacy students, and the most used medication was paracetamol.

Superparamagnetic Multifunctionalized Chitosan Nanohybrids for Efficient Copper Adsorption: Comparative Performance, Stability, and Mechanism Insights.

To limit the dangers posed by Cu(II) pollution, chitosan-nanohybrid derivatives were developed for selective and rapid copper adsorption. A magnetic chitosan nanohybrid (r-MCS) was obtained via the co-precipitation nucleation of ferroferric oxide (Fe3O4) co-stabilized within chitosan, followed by further multifunctionalization with amine (diethylenetriamine) and amino acid moieties (alanine, cysteine, and serine types) to give the TA-type, A-type, C-type, and S-type, respectively. The physiochemical characteristics of the as-prepared adsorbents were thoroughly elucidated. The superparamagnetic Fe3O4 nanoparticles were mono-dispersed spherical shapes with typical sizes (~8.5-14.7 nm). The adsorption properties toward Cu(II) were compared, and the interaction behaviors were explained with XPS and FTIR analysis. The saturation adsorption capacities (in mmol.Cu.g-1) have the following order: TA-type (3.29) > C-type (1.92) > S-type (1.75) > A-type(1.70) > r-MCS (0.99) at optimal pH0 5.0. The adsorption was endothermic with fast kinetics (except TA-type was exothermic). Langmuir and pseudo-second-order equations fit well with the experimental data. The nanohybrids exhibit selective adsorption for Cu(II) from multicomponent solutions. These adsorbents show high durability over multiple cycles with desorption efficiency > 93% over six cycles using acidified thiourea. Ultimately, QSAR tools (quantitative structure-activity relationships) were employed to examine the relationship between essential metal properties and adsorbent sensitivities. Moreover, the adsorption process was described quantitatively, using a novel three-dimensional (3D) nonlinear mathematical model.