A review of biocompatible polymer-functionalized two-dimensional materials: Emerging contenders for biosensors and bioelectronics applications.

Bioelectronics, a field pivotal in monitoring and stimulating biological processes, demands innovative nanomaterials as detection platforms. Two-dimensional (2D) materials, with their thin structures and exceptional physicochemical properties, have emerged as critical substances in this research. However, these materials face challenges in biomedical applications due to issues related to their biological compatibility, adaptability, functionality, and nano-bio surface characteristics. This review examines surface modifications using covalent and non-covalent-based polymer-functionalization strategies to overcome these limitations by enhancing the biological compatibility, adaptability, and functionality of 2D nanomaterials. These surface modifications aim to create stable and long-lasting therapeutic effects, significantly paving the way for the practical application of polymer-functionalized 2D materials in biosensors and bioelectronics. The review paper critically summarizes the surface functionalization of 2D nanomaterials with biocompatible polymers, including g-C3N4, graphene family, MXene, BP, MOF, and TMDCs, highlighting their current state, physicochemical structures, synthesis methods, material characteristics, and applications in biosensors and bioelectronics. The paper concludes with a discussion of prospects, challenges, and numerous opportunities in the evolving field of bioelectronics.

Rice husk valorization into sustainable Ni@TiO2/biochar nanocomposite for highly selective Pb (II) ions removal from an aqueous media.

Herein, we successfully prepared sustainable nanocomposites from agriculture waste (rice husk)-derived biochar precursor, and followed by nickel-doped, base-treated titanium dioxide nanomaterials loading for efficient lead (Pb2+) removal from aqueous media. By varying the loading contents of active materials, the optimized sample (Ni0.01@Na-TiO2/BC) possessed an efficient Pb2+ adsorption capability of 122.3 mg g-1 under the under optimum adsorption parameters, which is attributable to its specific surface area (138.09 m2 g-1) and excess functional sites. Kinetic and Isothermal examination illustrated that Pb2+ adsorption phenomena was well followed through pseudo 2nd order and Langmuir models. In addition, superior Pb2+ ions adsorption selectivity was recorded by optimized sample in a multi-metallic system over other existing ion (such as Cd2+, Mg2+, Ca2+, Cu2+, and Zn2+). Desorption experiments has been performed by using desorbing agent that demonstrates the good regeneration ability of sample. Hence, these findings provide new insight for the biowaste management by converting them into innovative adsorbents for commercial scale environmental remediation.

Innovative progress in graphene derivative-based composite hybrid membranes for the removal of contaminants in wastewater: A review.

Graphene derivatives (graphene oxide) are proved as an innovative carbon materials that are getting more attraction in membrane separation technology because of its unique properties and capability to attain layer-to-layer stacking, existence of high oxygen-based functional groups, and generation of nanochannels that successively enhance the selective pollutants removal performance. The review focused on the recent innovations in the development of graphene derivative-based composite hybrid membranes (GDHMs) for the removal of multiple contaminants from wastewater treatment. To design GDHMs, it was observed that at first GO layers undergo chemical treatments with either different polymers, plasma, or sulfonyl. After that, the chemically treated GO layers were decorated with various active functional materials (either with nanoparticles, magnetite, or nanorods, etc.). By preparing GDHMs, properties such as permeability, porosity, hydrophilicity, water flux, stability, feasibility, mechanical strength, regeneration ability, and antifouling tendency were excessively improved as compared to pristine GO membranes. Different types of novel GDHMs were able to remove toxic dyes (77-100%), heavy metals/ions (66-100%), phenols (40-100%), and pharmaceuticals (74-100%) from wastewater with high efficiency. Some of GDHMs were capable to show dual contaminant removal efficacy and antibacterial activity. In this study, it was observed that the most involved mechanisms for pollutants removal are size exclusion, transport, electrostatic interactions, adsorption, and donnan exclusion. In addition to this, interaction mechanism during membrane separation technology has also been elaborated by density functional theory. At last, in this review the discussion related to challenges, limitations, and future outlook for the applications of GDHMs has also been provided.

Chemically modified sugarcane bagasse-based biocomposites for efficient removal of acid red 1 dye: Kinetics, isotherms, thermodynamics, and desorption studies.

Novel eco-friendly and economically favourable chemically modified biosorbents and biosomposites from sugarcane bagasse (SB) has been investigated for the first time for efficient removal of Acid red 1 dye from wastewater. As fabricated biosorbents and biocomposites were characterized analytically. Batch adsorption experiments has been performed to optimize operating parameters and the determined optimum conditions are; pH: 2, dose: 0.05 g, contact time: between 60 and 75 min, initial dye concentration: 400 mg L-1, and temperature: 30 °C, at which maximum Acid red 1 dye removal capacities were found (within range of 143.4-205.1 mg g-1) by as-designed SB-derived chemically modified biosorbents and biocomposites. This high adsorption capacity was accompanied due to its large specific surface area (30.19 m2 g-1) and excessive functional active binding sites. In terms of the nature of adsorption process, kinetic and isothermal studies demonstrated that experimental data shows greater fitness with pseudo 2nd order and Langmuir model. Thermodynamics analysis revealed that the adsorption process is spontaneous, feasible, and exothermic in nature. Adsorption selective studies signifies that lower concentration of co-existing metallic ions were not interfered during the removal of Acid red 1 dye, which confirms that under optimized adsorption conditions the biosorbents and biocomposites exhibited greater affinity for dye molecules. The excessive quantity (82%) of loaded dye molecules within the adsorbents were extracted within the NaOH eluting media which predicts that as designed biocomposites could have capability of reusability. Hence, it is anticipated that this type of novel SB-derived biocomposites could be considered as greener potential candidate material for commercial scale dye removal applications from industrial wastewater.

Acetic acid-mediated cellulose-based carbons: Influence of activation conditions on textural features and carbon dioxide uptakes.

In this work, we developed a simple methodology for producing highly porous carbons. Herein, we combined the hydrothermal method with chemical activation to fabricate cellulose-based, melamine modified porous carbons, using acetic acid as an additive. The preparation conditions including activation temperature, activation time, and melamine ratio were varied to obtain an optimized adsorbent exhibiting efficient textural features and maximized carbon dioxide (CO2) adsorption uptake. By varying the preparation conditions, high specific surface area (SSA) (1260-3019 m2 g-1), microporosity in the range of 0.21-1.13 cm3 g-1, and a well-developed porous structure was obtained. The optimized adsorbent exhibits an excellent CO2 adsorption uptake of 297.05 mg g-1 (6.75 mmol g-1) and 174.4 mg g-1 (3.96 mmol g-1) at 273 K and 298 K at 1 bar, respectively, due to the existence of ultra-micropores (<0.68 nm, < 0.81 nm), high SSA (3019 m2 g-1), and high nitrogen content (8%). Furthermore, the role of micropores in the CO2 adsorption process suggests that micropores between 0.68 nm and 1 nm exhibit high CO2 adsorption potential. Additionally, all synthesized carbons exhibited a high isosteric heat of adsorption (45 kJ mol-1) and a greater affinity for adsorbed CO2 species than nitrogen (N2) molecules. Thus, as-fabricated porous carbon adsorbents are an effective competitor for CO2 uptake applications to mitigate global warming.

A Role of Activators for Efficient CO2 Affinity on Polyacrylonitrile-Based Porous Carbon Materials.

Herein, we investigated polyacrylonitrile (PAN)-based porous activated carbon sorbents as an efficient candidate for CO2 capture. In this research, an easy and an economical method of chemical activation and carbonization was used to generate activated PAN precursor (PAN-C) adsorbents. The influence of various activators including NaOH, KOH, K2CO3, and KNO3 on the textural features of PAN-C and their CO2 adsorption performance under different temperatures was examined. Among the investigated adsorbents, PANC-NaOH and PANC-KOH exhibited high specific surface areas (2,012 and 3,072 m2 g-1), with high microporosity (0.82 and 1.15 cm3 g-1) and large amounts of carbon and nitrogen moieties. The PAN-C activated with NaOH and KOH showed maximum CO2 uptakes of 257 and 246 mg g-1 at 273 K and 163 and 155 mg g-1 at 298 K, 1 bar, respectively, which was much higher as compared to the inactivated PAN-C precursor (8.9 mg g-1 at 273 K and 1 bar). The heat of adsorption (Q st) was in the range 10.81-39.26 kJ mol-1, indicating the physisorption nature of the CO2 adsorption process. The PAN-C-based activated adsorbents demonstrated good regeneration ability over repeated adsorption cycles. The current study offers a facile two-step fabrication method to generate efficient activated porous carbon materials from inexpensive and readily available PAN for use as CO2 adsorbents in environmental applications.

MnO2-decorated biochar composites of coconut shell and rice husk: An efficient lithium ions adsorption-desorption performance in aqueous media.

Lithium (Li+) is used in various applications involving pharmaceuticals, textile dyes, and batteries. Therefore, the demand for environmentally friendly and effective materials for Li+ uptake and recovery continues to increase. Herein, rice husk (RH) and coconut shell (CS) biomasses were used to fabricate honeycomb-networked biochar (BC) precursors via slow pyrolysis. RHBC- and CSBC-based MnO2 composites were synthesized by depositing MnO2 in various ratios onto RHBC and CSBC by varying the KMnO4 concentration (2%, 3%, and 4%), followed by simple ultrasonication and heat-treatment methodologies. The structural and physicochemical properties of all of the fabricated composites were analyzed using several different instrumental methods. The batch adsorption experiments were performed for comparative Li+-adsorption studies of RHBC-Mnx and CSBC-Mnx composites by optimizing several parameters (pH, adsorbent dose, Li+ initial concentration, and contact time). The comparative adsorption analysis revealed that the RHBC-Mnx composites exhibited stronger Li+-adsorption ability than the CSBC-Mnx composites and that increasing the MnO2 deposition to 3% in both cases led to maximum Li+ adsorption capacities (62.85 mg g-1 and 57.8 mg g-1), respectively. The kinetic studies show that Li+ adsorption proceeds through the pseudo-second-order mechanism. Li+ recovery was successfully carried out using HCl (eluting agent), thereby demonstrating the benefits of synthesized composites at the industrial scale. The current work indicates that the fabricated RHBC-Mnx and CSBC-Mnx composites may have potential for use as economical composites in eco-friendly applications such as Li+ adsorption and recovery from aqueous media.

Effect of nickel ion doping in MnO2/reduced graphene oxide nanocomposites for lithium adsorption and recovery from aqueous media.

Novel and effective reduced graphene oxide-nickel (Ni) doped manganese oxide (RGO/Ni-MnO2) adsorbents were fabricated via a hydrothermal approach. The reduction of graphite to graphene oxide (GO), formation of α-MnO2, and decoration of Ni-MnO2 onto the surface of reduced graphene oxide (RGO) were independently carried out by a hydrothermal technique. The physical and morphological properties of the as-synthesized adsorbents were analyzed. Batch adsorption experiments were performed to identify the lithium uptake capacities of adsorbents. The optimized parameters for Li+ adsorption investigated were pH = 12, dose loading = 0.1 g, Li+ initial concentration = 50 mg L-1, in 10 h at 25 °C. It is noticeable that the highest adsorption of Li+ at optimized parameters are in the following order: RGO/Ni3-MnO2 (63 mg g-1) > RGO/Ni2-MnO2 (56 mg g-1) > RGO/Ni1-MnO2 (52 mg g-1). A Kinetic study revealed that the experimental data were best designated pseudo-second order for each adsorbent. Li+ desorption experiments were performed using HCl as an extracting agent. Furthermore, all adsorbents exhibit efficient regeneration ability and to some extent satisfying selectivity for Li+ recovery. Briefly, it can be concluded that among the fabricated adsorbents, the RGO/Ni3-MnO2 exhibited the greatest potential for Li+ uptake from aqueous solutions as compared to others.

Effect of Triblock Copolymer on Carbon-Based Boron Nitride Whiskers for Efficient CO2 Adsorption.

Herein, we investigated novel carbon-containing P123 copolymer-activated boron nitride whiskers (P123-CBNW) fabricated via a structure directing approach followed by a single-step heat treatment under N2. The resulting materials were found to be highly micro- and mesoporous. The influence of the activating agent (P123 copolymer) on the CO2 adsorption efficiency was determined. The prepared samples possessed high specific surface areas (594-1732 m2/g) and micropore volumes (0.258-0.672 cm3/g). The maximum CO2 uptakes of the prepared adsorbents were in the range 136-308 mg/g (3.09-7.01 mmol/g) at 273 K and 1 bar and 97-114 mg/g (2.22-4.62 mmol/g) in the following order: CBNW < P123-CBNW3 < P123-CBNW2 < P123-CBNW1 < P123-CBNW0.5. The isosteric heat of adsorption values (∆Qst) were found to be 33.7-43.7 kJ/mol, demonstrating the physisorption nature of the CO2 adsorption. Extensive analysis revealed that the presence of carbon, the high specific surface area, the high microporosity, and the chemical structural defects within the adsorbents are responsible for raising the CO2 adsorption ability and the selectivity over N2 gas. The fabricated adsorbents show excellent regeneration ability after several repeated adsorption cycles, making the prepared adsorbents promising candidates for gas storage applications.

Functionalized Carbon Materials for Electronic Devices: A Review.

Carbon-based materials, including graphene, single walled carbon nanotubes (SWCNTs), and multi walled carbon nanotubes (MWCNTs), are very promising materials for developing future-generation electronic devices. Their efficient physical, chemical, and electrical properties, such as high conductivity, efficient thermal and electrochemical stability, and high specific surface area, enable them to fulfill the requirements of modern electronic industries. In this review article, we discuss the synthetic methods of different functionalized carbon materials based on graphene oxide (GO), SWCNTs, MWCNTs, carbon fibers (CFs), and activated carbon (AC). Furthermore, we highlight the recent developments and applications of functionalized carbon materials in energy storage devices (supercapacitors), inkjet printing appliances, self-powered automatic sensing devices (biosensors, gas sensors, pressure sensors), and stretchable/flexible wearable electronic devices.