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• Two poorly performing HCIC ligands were utilized to construct a dual-ligand system. • The dual-ligand system exhibited superior static and dynamic adsorption capabilities. • Molecular docking is used as an auxiliary tool to explain differences in selectivity. • The dual-ligand system separated antibodies from human serum with better performance. In conventional chromatographic ligand screening, underperforming ligands are often dismissed. However, this practice may inadvertently overlook potential opportunities. This study aims to investigate whether these underperforming ligands can be repurposed as valuable assets. Hydrophobic charge-induction chromatography (HCIC) is chosen as the validation target for its potential as an innovative chromatographic mode. A novel dual-ligand approach is employed, combining two suboptimal ligands (5-Aminobenzimidazole and Tryptamine) to explore enhanced performance and optimization prospects. Various dual-ligand HCIC resins with different ligand densities were synthesized by adjusting the ligand ratio and concentration. The resins were characterized to assess appearance, functional groups, and pore features using SEM, FTIR, and ISEC techniques. Performance assessments were conducted using single-ligand mode resins as controls, evaluating the selectivity against human immunoglobulin G and human serum albumin. Static adsorption experiments were performed to understand pH and salt influence on adsorption. Breakthrough experiments were conducted to assess dynamic adsorption capacity of the novel resin. Finally, chromatographic separation using human serum was performed to evaluate the purity and yield of the resin. Results indicated that the dual-ligand HCIC resin designed for human antibodies demonstrates exceptional selectivity, surpassing not only single ligand states but also outperforming certain high-performing ligand types, particularly under specific salt and pH conditions. Ultimately, a high yield of 83.9 % and purity of 96.7 % were achieved in the separation of hIgG from human serum with the dual-ligand HCIC, significantly superior to the single-ligand resins. In conclusion, through rational design and proper operational conditions, the dual-ligand mode can revitalize underutilized ligands, potentially introducing novel and promising chromatographic modes. [ABSTRACT FROM AUTHOR]

Adsorption is a low-energy, economical, and efficient method for pollutant removal from water. Because of their unique structure, large specific surface area (SSA), and non-toxicity, bismuth-based semiconductors, usually researched for the photodegradation of organic molecules, are also excellent for dark adsorption processes. Here, a three-dimensional adsorbent with a heterostructure with a hydrangea-like shape made of Bi2MoO6 (BMO) and BiOI (BOI) was synthesized by a one-pot solvothermal process and investigated for the adsorption of toxic dyes. BOI/BMO with an I-to-Mo ratio of 2.0 adsorbed 98.9% of the model pollutant rhodamine B (RhB) within 5 min with a maximum adsorption capacity of 72.72 mg/g in the dark at room temperature. When compared to pure BMO, the BOI2/BMO heterostructure was 14.1 times more performant because of its flower-like morphology with multiple planes, an SSA that was 1.6-fold larger, increased porosity, the formation of heterojunctions, and a negative surface charge attracting RhB. Further investigation indicated that adsorption by BOI2/BMO fitted the pseudo-second-order kinetic and the Langmuir isotherm models. In addition, the thermodynamic analysis showed that it was a spontaneous exothermic process probably relying on physisorption. Thus, the BOI/BMO adsorbent developed here is promising for the fast removal of toxic dyes from industrial wastewater. [ABSTRACT FROM AUTHOR]

Combining pre-oxidation with activated carbon adsorption was explored as an ideal approach for removing iodine from water source to eliminate the formation of Iodinated trihalomethanes (I-THMs). Compared with permanganate and monochloramine, chlorine is more suitable as pre-oxidant to obtain higher active iodine species (HOI/I 2). Active iodine species adsorption using both powdered activated carbon (PAC) and granular activated carbon (GAC) can be well fitted the pseudo-second-order kinetic model indicating that chemical adsorption was the dominant mechanism for HOI/I 2 adsorption. The average pore size of activated carbons was the most strongly correlated with the adsorption capacity (R2 > 0.98), followed by methylene blue (R2 > 0.76), pore volume (R2 > 0.70) and iodine number (R2 > 0.67). Moreover, three models, including intraparticle diffusion, Byod kinetic, and diffusion-chemisorption were used to illustrate the mechanisms of HOI/I 2 adsorption. Chemical adsorption was the dominant mechanism for HOI/I 2 adsorption. In summary, at the molar ratio of [NaClO] and [I−] as 1.2, pre-chloriantion time of 5 min, subsequently dosage of 15 mg/L of PAC E with 20 min adsorption can remove 79.8% iodine. In addition, the combined process can eliminate 61%–87.2% of I-THMs in the subsequent chlor(am)ination. The results indicate that pre-chlorination combined with PAC can effectively removed HOI/I 2 and attenuate I-THMs formation in the subsequent disinfection process. [Display omitted] • Optimizing prechlorination can enhance HOI/I 2 formation, facilitating subsequent adsorption. • Active iodine species (HOI/I 2) were chemically adsorpted by PACs and GACs. • HOI/I 2 adsorption followed pseudo-second-order kinetics. • Film diffusion was the rate-limiting process for HOI/I 2 adsorption on activated carbon. • Pre-chlorination with PAC adsorption can effectively remove HOI/I 2 and attenuate I-THM formation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Zr-doped Fe-MOFs/GO nanocomposites were successfully fabricated by an in-situ growth approach. • FeZr-MOFs/GO nanocomposites delivered an excellent adsorption capacity of up to 91.69 mg·g−1. • Appropriate doping of Zr(IV) led to a substantially improved water stability of MIL-101(Fe)/GO. • Adsorption mechanism of As(V) on FeZr-MOFs/GO was ascribed to chemical complexation and hydrogen bonding. Eliminating arsenic contaminants has become an imperative issue due to its persistent and serious harm to the environment and human health. Herein, a novel FeZr-MOFs/GO nanocomposite for effectively removing As(V) was fabricated by growing Fe-based metal–organic frameworks (Fe-MOFs) of MIL-101(Fe) on the graphene oxide (GO) surface with the addition of Zr(IV) dopants. The presence of GO, the doping amount of Zr ions, and the functional groups of the ligands were found to have an impact on the adsorption performance of Fe-MOFs. Notably, doping an appropriate amount of Zr(IV) resulted in a significant increase in water stability of MIL-101(Fe) and MIL-101(Fe)/GO nanocomposites. This improvement, along with chemical complexation and hydrogen bonding, played a pivotal role in the adsorption of As(V). The optimized FeZr-MOFs-0.2/GO (0.2 represented the molar ratio between Zr and Fe) nanocomposites demonstrated superior As(V) adsorption performance with an adsorption capacity of up to 91.69 mg·g−1. Moreover, this system proven effective across a wide range of pH (2–10) and environmental matrices. This study not only provides attractive MOF nanocomposites for broadening the application of aqueous solutions, but also opens up a novel avenue for the rational design and development of nanocomposites with exceptional properties and stability. [ABSTRACT FROM AUTHOR]

[Display omitted] • N-doped porous carbon (NPC) was fabricated via a novel one-step solvent-free melt polycondensation. • Potassium citrate served as both a template and an activator to create abundant microporous structure. • NPC delivered an excellent CO 2 adsorption capability at 4.16 mmol·g−1 at 100 kPa. • NPC exhibited a fast adsorption kinetics and an outstanding uninterrupted recyclability. • The CO 2 adsorption mechanism on NPC was ascribed to multi-layer adsorption by the micropore filling. Heteroatomic doped porous carbon (HPCs) is a promising advanced material, showing great application potential in greenhouse gas capture. Here, in-situ N-doped porous carbon (NPC) was developed via a novel and readily scalable strategy − one-step solvent-free melt polycondensation assisted by organic potassium salts, followed by pyrolysis and activation. As both a template and an activator, the added C 6 H 5 K 3 O 7 played an important role to create abundant microporous structure. The as-fabricated NPC-650–0.5 showed a rich N content (6.11 at.%), abundant narrow micro-porosity (0.3437 cm3·g−1), and a high surface area (1209.37 m2·g−1) and delivered an excellent CO 2 static adsorption capacity (4.16 mmol·g−1 and 8.40 mmol·g−1 at 100 and 500 kPa), a fast adsorption kinetics (circa 98% of balance capacity in 12 min), moderate heat of adsorption (25 to 30 kJ/mol), high selectivity of CO 2 /N 2 , and outstanding uninterrupted recyclability. Both the narrow micropore volume and N-doping sites had strong effects on the CO 2 adsorption capacity, indicating a physical and chemical adsorption process with the mechanism being multi-layer adsorption by the micropore filling. This work highlights the great potential of the NPC-650–0.5 for capturing CO 2 and offers new insights into a green activator and a simple and easy-to-scale method for preparing HPCs. [ABSTRACT FROM AUTHOR]

The low cost and non-toxic of magnesium oxides make it a potential eco-friendly material for arsenic removal. Polysaccharide is a kind of green modifier to obtain nanoscale MgO particles with a higher adsorption affinity. In this study, the impact of chain structures of polysaccharides on the morphology features and arsenate removal efficiency of MgO-NPs were investigated. Pullulan and starch facilitated the synthesis of flower-like MgO-NPs, and pectin facilitated the synthesis of plate-like ones. Although the two kinds of flower-like MgO-NPs undergone similar time to reach equilibrium, the one obtained from the starch-synthesis route showed a higher arsenate adsorption capacity (98 mg g−1), due to that their bushy and smaller petals on the surface provide more active sites for arsenic adsorption. The pectin-synthesis route also produced MgO-NPs with higher arsenate adsorption capacity (101 mg g−1), ascribed to stacking of nano-plates on their surfaces facilitated to form defect surfaces. However, due to their lower BET area, the plate-like MgO-NPs took twice times to reach equilibrium for arsenic adsorption compared with the others. In the stage for the hydrolysis of MgO, hydroxyl groups on the polymer chain provide active sites to physically trap or bond with MgO particles and then to produce hydrolyzed precursors. The poly chain containing inter- and intra-hydroxyl groups directed MgO molecular growing into hydroxide crystals with 3D frameworks during their nucleation and growth. However, pectin only provides inter-hydroxyl groups and directs to form hydroxides with 2D frameworks. Furthermore, the rapid-nucleation vs. slow-growth model in the stage of pyrolysis of hydroxide crystals successfully interprets the thinner petals and complex chemical phases of the final nanoparticles obtained from the pullulan-synthesis route. This work may provide direction and perspectives for the rational design of well-performing MgO materials for arsenate removal. [Display omitted] • Ploymorphous MgO-NPs for efficient arsenate removal were synthesized. • Pullulan and starch facilitated to synthesize MgO nano-flowers. • Pectin helped to synthesize MgO nano-plates. • Polysaccharide's structure controls the formation of 2D or 3D nanoparticles. • Small flower-like and plate-like structures are benefit to arsenate removal. [ABSTRACT FROM AUTHOR]

[Display omitted] • Magnetic Fe 3 O 4 /GO nanocomposites were synthesized using solvothermal and pyrolysis methods. • Fe 3 O 4 /GO nanocomposite exhibited a fully-formed MOF morphology and crystal structure. • Fe 3 O 4 /GO nanocomposite delivered a remarkable adsorption capacity of 49.88 mg/g at 298.15 K. • Fe 3 O 4 /GO nanocomposite displayed excellent resistance to ionic interference and wide pH applicability. • The adsorption mechanism of As(V) was ascribed to both chemical complexation and electrostatic interaction. The urgent need to remove arsenic from groundwater stems from the irreversible damage it causes to aquatic systems and biological health. In this study, unique magnetic Fe 3 O 4 /graphene oxide (GO) nanocomposites derived from MIL-100(Fe)/GO precursor were rationally and precisely developed by combination of solvothermal synthesis and pyrolysis methods. The optimized MIL-100(Fe)/1%GO-400 magnetic nanocomposite (where 1% and 400 represent the mass ratio of GO to MIL-100(Fe) and pyrolysis temperature, respectively) exhibited exceptional adsorption capacity for As(V) and possessed magnetic separation properties. The novel nanocomposite had complete MOF morphology and crystal structure, as well as good resistance to interference from ions and could be used effectively over a wide pH range (2–9) for adsorption of As(V). The As(V) adsorption on the nanocomposite was found to follow the pseudo-second-order (PSO) kinetic model and Temkin adsorption isotherm model, as well as a spontaneous endothermic process dominated by chemisorption. The incorporation of GO and pyrolysis of the Fe-MOFs was proven to enhance the adsorption capacity of nanocomposite, water stability, and magnetic recovery ability. The adsorption mechanism was attributed to the synergistic effect of chemical complexation, hydrogen binding and electrostatic interaction. This work not only presents a feasible strategy for the development of Fe-MOFs-based derivatives, but also offers a promising approach to expanding the application of functional Fe-MOFs-based derivatives in arsenic-contaminated wastewater treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • The P-doped biochar was derived from pyrolysis of phytic acid-activated lemon peel. • The CuSiO 3 /PBC composite was synthesized by loading CuSiO 3 on the P-doped biochar. • Such CuSiO 3 /PBC delivered NH 3 adsorption capacity of 6.36 mmol/g at 298 K and 1 bar. • The NH 3 adsorption on CuSiO 3 /PBC was verified a reactive adsorption process. Ammonia (NH 3) is a typical malodorous pollutant and one of the key factors causing PM2.5. It is of great significance to develop an efficient material with outstanding adsorption ability for NH 3 capture. Herein, a novel CuSiO 3 /PBC composite adsorbent is fabricated by first producing phosphorous-doped porous biochar (PBC) via pyrolysis of lemon peel with phytic acid as both the phosphorous source and activator, and subsequent loading of cupric silicate (CuSiO 3) onto the PBC with an ultrasonic dipping process. Among these as-fabricated composites, the CuSiO 3 /PBC-2-500-0.2 adsorbent (where 2 = the mass ratio of phytic acid to LP; 500 = the activation temperature; 0.2 = the atomic percentage of Cu) with a large surface area of 726.3 m2 g−1 delivers an excellent NH 3 batch adsorption ability of 6.36 mmol g−1 at 298 K and 1 bar, and a high dynamic adsorption ability of 1.96 mmol g−1 under 200 ppm NH 3 and a total flow rate of 50 mL min−1. The CuSiO 3 /PBC-2-500-0.2 composite also maintains circa 80% of the initial adsorption capacity after 8 cycle reuses, conducive to continuous operation. Furthermore, the postulated adsorption mechanism is demonstrated that NH 3 reacts with acidic sites such as H+ of HPO 4 2− to form NH 4 + and forms [Cu(NH 3) 4 ]2+ with Cu2+, and the porous structure of the composite material also plays an important role. This work not only provides a promising adsorbent for NH 3 capture, but also displays a novel idea for the development of excellent composite adsorbents derived from biomass waste. [ABSTRACT FROM AUTHOR]

[Display omitted] • ECSs are reused as an adsorbent for Cr(VI) from wastewater. • The maximum experimental removal capacity of ECSs for Cr(VI) was 110.50 mg/g. • Removal mechanisms include redox, electrostatic adsorption, and flocculation. Exhausted copper slags (ECSs) are secondary slags produced in the reusing process of copper smelting fly ashes and have the potential to synthesize adsorbent for the elimination of toxic elements. This study focuses on the potential of the original ESCs for the detoxication and removal of Cr(VI) from aqueous solutions. Batch adsorption experiments showed that ESCs present an excellent performance on Cr(VI) eliminate, and the maximum adsorption capacity is 110.50 mg∙g−1 at acid solutions (pH = 2) with a mild temperature condition (308 K). Furthermore, the adsorption efficiency of Cr was barely effected by the comment co-existing elements, such as NO 3 – and SO 4 2-, indicating its specific adsorption capacity for Cr. The elimination of Cr onto ESCs fits well with the Langmuir adsorption model, indicating that the adsorption process was controlled by monolayer adsorption. Moreover, Cr(VI) adsorption onto ESCs also followed the Pseudo-second-order kinetics with the adsorption rate constant k at 2.65 × 10-3 g·mg−1·min−1. Mechanistic analysis indicated that ECSs eliminated Cr(VI) by electrostatic adsorption and flocculation precipitation, and reduced Cr(III) by Fe2+, Mo2+, S2-, and SO 3 2-. The environmental risks during its adsorption implication process were also accessed and the toxic elements, such as Cu, As, and Pb in the materials were barely detected in the residue solutions. Thus, ECSs could be used as a facile and cost-effective adsorbent for Cr(VI) removal, even without any further pre-treatment process, which is meaningful to the disposal of this typical industrial waste. [ABSTRACT FROM AUTHOR]

[Display omitted] • PPy/NP were synthesized via an in situ chemical polymerization technique. • The maximum adsorption capacity of Cr(VI) on PPy/NP was 261.78–395.26 mg/g. • PPy/NP showed an excellent performance for adsorption and reduction of Cr(VI). • Cr(VI) removal was attributed to ion exchange, adsorption and reduction. • PPy/NP could be a promising material for efficient removal of Cr(VI). Easily agglomeration of polypyrrole (PPy) significantly limits its practical applications. In this study, natural pyrite (NP) was applied to disperse PPy and overcome this agglomeration; a novel composite of PPy/NP was synthesized and applied for the efficient removal of hexavalent chromium [Cr(VI)] from aqueous solutions. Results showed that the PPy/NP composites exhibited better Cr(VI) removal performance than PPy alone. This enhanced removal capacity is attributed to the addition of NP, which prevents PPy agglomeration and reduces Cr(VI) to trivalent chromium[Cr(III)]; Cr(VI) removal was significantly dependent on the solution's pH. The sorption kinetics of Cr(VI) with PPy/NP was described by the pseudo-second-order model and Elovich models, which highlight the chemicalsorption process. The sorption isotherm was well simulated by Langmuir model and the maximum adsorption capacity of Cr(VI) on PPy/NP was 261.78–395.26 mg/g at 303 – 323 K, which is significantly higher than that of PPy alone (124.84–194.17 mg/g). Thermodynamic analyses confirmed that this adsorption process was spontaneous and endothermic. PPy/NP composites could be used as a recyclable absorbents for four Cr(VI) reduction cycles without any evident loss in adsorption performance. The mechanism Cr(VI) removal by PPy/NP composites is attributed to ion exchange (9.47 %), adsorption (31.03 %), and reduction (59.50 %). [ABSTRACT FROM AUTHOR]

[Display omitted] • Functionally-designed adsorbent hydrogel beads were synthesized by a simple method. • The g-C 3 N 4 /CS/PVA hydrogel beads showed high adsorbing capacity for SMX. • Interactions between hydrogel and SMX were inferred to the electrostatic interactions and hydrogen bonds. • The hydrogel beads could be regenerated by light. Adsorption method has been widely used in the removal of emerging contaminants. However, many adsorbents are puzzled by key obstacles for effective and simple regeneration. In this work, the functionally-designed graphitic carbon nitride (g-C 3 N 4) embedded chitosan-polyvinyl alcohol composite (g-C 3 N 4 /CS/PVA) hydrogel beads were synthesized for the adsorptive removal of sulfamethoxazole (SMX) from water, and they could be regenerated by light. The adsorption kinetics, isotherm, thermodynamics, and impacting factors were systematically investigated. And the adsorption capacity of the hydrogel for SMX was relatively stable at pH of 4–8, with the maximum adsorption capacities being 5.8 mg g−1 at pH 5. The main adsorption force may be inferred to the electrostatic interactions between SMX and hydrogel beads, and hydrogen bonds between the amino or hydroxyl groups of the hydrogel and the amino of the SMX. The dominance of electrostatic interactions resulted in SMX adsorption being highly dependent on ionic strength. Being irradiated with an ultraviolet lamp for 5 recycles, the hydrogel beads still kept good adsorption capacity. The regeneration behavior was attributed to the photocatalytic degradation of SMX by g-C 3 N 4. Namely, photocatalytic oxidation reactivated the adsorption sites and increased the release of adsorbed pollutants with improved desorption performance. [ABSTRACT FROM AUTHOR]