Saturation Capacity Research Articles

Using Activated carbon of Date Seeds for the Removal of Methyl Red from aqueous Solutions

In this study, the activated carbon that was obtained from date seeds, after heating at 500 ºC, was used to remove methyl red dye from its aqueous solutions. Different parameters were applied including (the effect of dose, the effect of adsorption time, and the effect of pH value). The extent of dye removal increased with increasing adsorption time. An acidic pH is optimal for enhancing dye adsorption. The Langmuir isotherm was applied to the data obtained, and its constants were calculated at the optimum conditions. According to Langmuir isotherm, the monolayer saturation capacity (q m ) is 0.9 mg/g. The study concludedthat date seeds activated carbon (DSAC) has demonstrated effective adsorption results in removing methyl red and suggests its potential for use in other adsorption studies.

Biogeochemical interaction between thallium (Tl) and schwertmannite in acidic environment and the anti-dissolution mechanisms of Tl(I)-coprecipitated schwertmannite

Highly toxic thallium (Tl) can be released into the environment through acid mine drainage (AMD). However, our knowledge on the biogeochemical processes of Tl in such acidic, iron (Fe)-rich environments is limited. Here, we show that schwertmannite, a naturally formed Fe(III) mineral in AMD, can effectively immobilize Tl(I) through coprecipitation and adsorption. Tl(I) coprecipitation into schwertmannite removed a large portion of Tl(I) under a wide range of initial Tl(I) concentrations (0.01~1.0mg/L) and within a short duration (48h). The saturated adsorption capacities of the biosynthetic and chemically synthesized schwertmannite for Tl(I) (1.0mg/L) were 1.96 and 1.59mg/g, respectively, under acidic conditions (pH=3.0). The kinetic dissolution results indicated that biogenic Tl-coprecipitated schwertmannite exhibited greater stability, which was attributed mainly to the elevated extent of Tl oxidation and enhanced crystallinity of Tl-bearing schwertmannite. The extended X-ray absorption fine structure (EXAFS) analyses revealed that the incorporation of Tl into schwertmannite involves the heterovalent substitution of Fe(III) by the formation of double-corner sharing linkages between the Tl-O tetrahedra and Fe-O octahedra. These results suggested that coprecipitation combined with adsorption can achieve retention of Tl in acidic environment throughout the entire mineralization process of schwertmannite, which provides a comprehensive understanding of biogeochemical fate of Tl in AMD-affected areas.

Designing Phenolphthalein-Based Adsorptive Membranes for the High-Affinity, High-Capacity Capture of Contaminants from Water.

The selective removal of solutes is crucial for ensuring a sustainable water supply, recovering resources, and cost-effective biomanufacturing. Adsorptive membranes are promising in this regard due to their rapid mass transfer and low energy demands. However, state-of-the-art adsorptive membranes offer limited pore sizes and surface chemistries. This study reports the development of adsorptive membranes from reactive phenolphthalein-based (PPH-based) polymers. These polymers, which are molecularly engineered to possess a high density of reactive pendant groups, are transformed into porous membranes through a surface-segregation vapor-induced phase separation (SVIPS) method. Examining the thermodynamic characteristics of the polymer-solvent-nonsolvent system informs the SVIPS manufacturing process and facilitates the formation of diverse membrane morphologies with hydraulic permeabilities ranging from 3400 to 13,500 L m-2 h-1 bar-1. Copper ion binding experiments demonstrate a saturation capacity of 0.9 mmol Cu2+ g-1, indicating high accessibility of the pendant groups for postsynthetic modification. Functionalization with alkyne groups enables one-step click reactions, such as the thiol-yne and Cu(I)-catalyzed azide-alkyne cycloaddition, expanding the membrane functionality. The incorporation of cucurbit[7]uril-azide macrocycles demonstrates the affinity-mediated capture of methyl viologen from solution. The combination of PPH-based polymers and the SVIPS method provides a versatile adsorptive membrane platform with a dense presentation of reactive sites, facilitating customization through diverse and high-yielding reactions.

Association between iron metabolism and acute kidney injury in cardiac surgery with cardiopulmonary bypass: a retrospective analysis from two datasets

ObjectiveWe sought to explore the linear or nonlinear relationship between preoperative iron metabolism and acute kidney injury following cardiac surgery (CSA-AKI) with cardiopulmonary bypass (CPB).MethodsPatients who underwent cardiac surgery with CPB between December 2018 and April 2021 were retrospectively collected from Fuwai Hospital and Medical Information Mart for Intensive Cared dataset (MIMIC-IV). The measurements of iron metabolism included serum iron (SI), serum ferritin (SF), transferrin (TRF), transferrin saturation (TS), and total iron binding capacity (TIBC). Logistic regression and restricted cubic spline (RCS) were used for linear and nonlinear analysis. The primary outcome was postoperative AKI with 48 h after cardiac surgery.ResultsOf 10,639 patients screened (2420 in Fuwai Hospital and 8219 in MIMIC-IV dataset),1488 eligible patients were enrolled for the final analysis (Fuwai Hospital: n = 744, MIMIC-IV: n = 744).The incidence of AKI was 25.7% and 56.5%, respectively. Logistic regression showed that the levels of TRF (odds ratio (OR) = 1.53,95%CI:1.01–2.14, p = 0.012) and TIBC (OR = 1.05,95%CI:1.02–1.07, p < 0.001) were independent risk factor for AKI. Moreover, in the spline models adjusted with age (median:56), female, and history of diabetes, a significant statistical difference was observed between SI, SF, TRF, TS, TIBC (p for nonlinear < 0.05) and AKI in the Fuwai Hospital dataset. Additionally, the levels of SI (p for nonlinear 0.0364),SF (p for nonlinear 0.0461) were also in non-linear relationship with AKI in the MIMIC-IV dataset.ConclusionIron metabolism markers (SI, SF, TS, TRF, and TIBC) displayed a nonlinear relationship with AKI by the RCS model (adjusted by age, gender, and history of diabetes). Notably, the MIMIC-IV dataset, which includes elderly patients, also demonstrated a nonlinear relationship between SI, SF and AKI. These findings highlight the potential therapeutic value of targeting proteins related to iron metabolism in patients with AKI.Clinical trial numberNot applicable.

Convenient synthesis of granulated Li/Al-layered double hydroxides/chitosan composite adsorbents for lithium extraction from simulated brine with a high Mg2+/Li+ ratio

Lithium/aluminum layered double hydroxides (LDH) have been industrially applied to extract lithium from salt-lake brine. Different from traditional granulation methods, chitosan with high hydrophilicity was used as the binder of LDH in this work, and LDH/chitosan composite hydrogel granules (CLDH) with a diameter of about 1–2 mm were successfully prepared. The new granulation method is simple, cost-effective, and does not require the use of organic solvents. The chemical composition and structure of CLDH were characterized by techniques such as FTIR, XRD, FESEM, TEM, TGA, and XPS. In simulated brine with a Mg2+/Li+ ratio of 102, the maximum saturated adsorption capacity of lithium on CLDH-3 reached 12.5 mg g−1 (pH = 6.5), but it took 24 h to reach adsorption equilibrium. During the three successive cycles for the extraction of Li+ from simulated brine by the CLDH-3 column at the flow rate of 1 mL min−1, the adsorption capacities of Li+ on CLDH-3 in the three cycles were 15.4, 15.9 and 12.1 mg g−1, respectively. Moreover, deionized water (30 °C) was used as the eluent to recover lithium adsorbed on the CLDH-3 column, and the lithium recovery efficiencies reached 50.7 %, 53.6 %, and 62.8 % of the column adsorption capacities over the three cycles, respectively, and the Mg/Li ratios in the eluents were 0.47, 0.71, and 0.50, respectively. Overall, CLDH-3 exhibits good reusability, mechanical strength, structural stability, and selectivity in the process of lithium extraction from simulated salt-lake brine, and has potential industrial application value.

Design and utilisation of a novel poly imino-phosphorane composite for the effective removal of Pb2+ and Cr3+ ions from contaminated water sources

ABSTRACT This study introduces a novel chitosan-immobilised imino-phosphorane composite (Chi-iph) for the efficient removal of lead (Pb2+) and chromium (Cr3+) from wastewater. The successful synthesis of Chi-iph was confirmed using FT-IR, XPS, BET, EDX, TGA, 1H-NMR, 13C-NMR, EI/MS, and ICP-OES analyses. Various experimental parameters such as pH, equilibrium time, metal concentration, adsorbent dose, temperature, and eluents were optimised to enhance the adsorption performance. At 25°C, with pH values of 5.5 for Pb2+ and 4.5 for Cr3+, an initial concentration of 200 mg/L, and an agitation time of 20 min, the maximum adsorption capacities were 55 mg/g for Pb2+ and 45 mg/g for Cr3+. Kinetic modelling demonstrated that the pseudo-first-order model best predicted the adsorption process, yielding capacities of 56.65 mg/g for Pb2+ and 46.38 mg/g for Cr3+. Isotherm analysis showed that the Langmuir model was a better fit than the Freundlich model, with theoretical capacities of 56.81 mg/g for Pb2+ and 44.64 mg/g for Cr3+. The Dubinin–Radushkevich (D-R) isotherm revealed adsorption energy (E) values of 9.45 kJ/mol for Pb2+ and 8.64 kJ/mol for Cr3+, indicating a chemisorption process. Theoretical saturation capacities (qD) were 56.28 mg/g for Pb2+ and 45.58 mg/g for Cr3+. Temkin isotherm results, with bT values of 9.71 and 8.53 kJ/mol for Pb2+ and Cr3+ respectively, aligned closely with the D-R model, further confirming chemisorption. Thermodynamic studies indicated that the adsorption process is exothermic, spontaneous, and more favourable at lower temperatures. Complete desorption of the heavy metals was achieved using 1 M HNO₃, allowing for efficient metal recovery. In a practical application, the Chi-iph composite removed 11.5 mg/L of Pb2+ and 7.01 mg/L of Cr3+ from contaminated wastewater, demonstrating its potential for environmental remediation. The composite’s performance aligns with WHO and FAO guidelines, making it suitable for treating wastewater before disposal into marine environments.

Alterations of Hepcidin and Iron Markers Associated with Obesity and Obesity-related Diabetes in Gambian Women

Aims Obesity, type 2 diabetes (T2D), and chronic inflammation are associated with disturbances in iron metabolism. Hepcidin is hypothesized to play a role in these alterations owing to its strong association with inflammation via the JAK-STAT3 pathway. The current study investigated the differences between inflammatory markers and iron indices and their association with hepcidin in lean women, women with obesity, and women with obesity and T2D (obesity-T2D) in The Gambia. Materials and methods In a cross-sectional study design, fasted blood samples were collected from three groups of women: lean women (n=42, body mass index (BMI)=20.9 kg/m2), women with obesity (n=48, BMI=33.1 kg/m2) and women with obesity-T2D (n=30, BMI=34.5 kg/m2). Markers of inflammation (IL-6 and CRP) and iron metabolism [hepcidin, iron, ferritin, soluble transferrin receptor (sTfR), transferrin, transferrin saturation, and unsaturated iron-binding capacity (UIBC)] were compared using linear regression models. Simple regression analyses were performed to assess the association between hepcidin levels and respective markers. Results Women with obesity and obesity-T2D showed elevated levels of inflammatory markers. There was no evidence that markers of iron metabolism differed between lean women and obese women, but women with obesity-T2D had higher transferrin saturation, higher serum iron concentration, and lower UIBC. Serum hepcidin concentrations were similar in all the groups. Hepcidin was not associated with markers of inflammation but was strongly associated with all other iron indices (all P&lt;0.002). Conclusion Contrary to our original hypothesis, hepcidin was not associated with markers of inflammation in the three groups of Gambian women, despite the presence of chronic inflammation in women with obesity and obesity-T2D.

Fusion of Hydrophobic Anchor Peptides Promotes the Hydrolytic Activity of PETase but not the Extent of PET Depolymerization

AbstractEnzymatic recycling of polyethylene terephthalate (PET) has attracted significant attention in recent years. While the fusion of anchor peptides to PET hydrolases is believed to enhance PET hydrolytic activity, a quantitative analysis is yet lacking. Here, we construct four fusion enzymes by fusing anchor peptides (including hydrophobic LCI, LCIM1 and TA2, and hydrophilic EK4) to the C terminus of HotPETase, one of the most active PET hydrolases for high‐crystallinity PET (HC‐PET). Single‐molecule force spectroscopy (SMFS) demonstrates that hydrophobic anchor peptides promote adhesive interactions between the fusion enzymes and the PET surface. This is also validated by the adsorption kinetics and isotherms, and the saturated adsorption capacity remains unaltered compared to HotPETase. At low substrate loadings, the apparent hydrolytic activity of these fusion enzymes is positively related to the hydrophobicity of the anchor peptides. Among them, HotPETase‐LCI stands out as the most effective enzyme for HC‐PET degradation, demonstrating a 1.5‐fold increase in hydrolytic activity. At high substrate loadings, the advantages of fusion with anchor peptides diminish. We conclude that fusion enzymes only facilitate the hydrolytic rates of reactions for HC‐PET but have little effect on the final conversion extent.

Binding energy crossover mechanism enables low-temperature hydrogen storage performance of dual-phase TiZrCrMnNi(VFe) high-entropy alloy

High-entropy hydrogen storage alloys possess immense potential for composition-performance modulation, yet they currently struggle to strike a balance between high capacity, stability, and low-temperature dehydrogenation. In this work, a novel TiZrCrMnNi(VFe) high-entropy alloy (HEA) was designed and dual-phase synergistic effect during the de-/hydrogenation processes was proposed. Specifically, the as-synthesized TiZrCrMnNi(VFe) alloy comprises two approximate C14 Laves phases, denoted as C14-Ⅰ and C14-Ⅱ phases. A noteworthy feature is that TiZrCrMnNi(VFe) HEA can rapidly reach a saturated capacity of 1.83 wt% H2 at 0 °C without any activation treatment, and then desorb 1.77 wt% H2 with a low onset dehydrogenation temperature of 20 °C. Based on experimental evidence and DFT calculations, it is concluded that dual-phase structure offers a distinguished phenomenon of binding energy crossover. Accordingly, compared with a single C14 phase, the structure with two C14 phases produces dual-phase synergistic effect, facilitating the de-/hydrogenation processes by lowering the energy barrier. In addition, the existence of phase boundaries also improves the activation performance of the alloy. Consequently, TiZrCrMnNi(VFe) HEA has excellent activation and low-temperature de-/hydrogenation performance. The innovative outcomes here provide a valuable reference for subsequent research on the low temperature de-/hydrogenation of HEAs.

Synthesis, characterization and study of Sb(Ⅲ) adsorption from aqueous solution by iron-aluminum pillared attapulgite

In this study, a simple, environmentally friendly and inexpensive adsorbent for Sb(III) in aqueous solution was prepared by the copolymerization method using attapulgite as the matrix, FeCl3 and AlCl3 as the metal sources. The morphology and structure of iron-aluminum pillared attapulgite were analyzed through various characterization methods. The conditions and influencing factors of iron-aluminum pillared attapulgite preparation and Sb(III) adsorption were studied. The saturated adsorption capacity of Sb(III) could reach 60.44 mg·g−1 for 180 min at pH 7 and 298 K. The adsorption process is conformed to Langmuir isothermal model and pseudo-second-order kinetic model, and the thermodynamic investigation suggested a spontaneous and endothermic adsorption process. It was revealed by X-ray photoelectron spectroscopy analysis and Zeta potential analysis that Sb(III) was first electrostatically adsorbed by the adsorbent, part of Sb(III) was oxidized to Sb(V) by Fe(III) and then antimony was complexed with iron and aluminum hydroxides to form surface complexes. In addition, a small amount of antimony migrated through intra-particle diffusion into the internal micropores and reacted with hydroxyl groups. Most coexisting components under the chosen conditions had no influence on Sb(III) adsorption, and PO43−, AsO33−, C6H8O7 and H2C2O4 had a negligible effect. However, the adsorption capacity of over 90 % without interference showed that the material has a strong selectivity for Sb(III) adsorption. The findings of the desorption experiment showed that the adsorption product has a considerable degree of desorption at increased hydrochloric acid concentrations. It may be concluded that the adsorption product is more stable in the overall polluted water environment since the actual acidity of the polluted water environment is significantly lower than the desorption experiment acidity. Overall, iron-aluminum pillared attapulgite has great potential for application in removing Sb(III).

Experiment on selective dynamic extraction of germanium by ultrasonic enhanced N235 extraction resin under complex system

Germanium plays an irreplaceable role in the field of modern high-tech materials and is an important strategic metal resource. N235 extraction resin was used to selectively extract [Ge(C4O6H4)3]2-. Under the condition of ultrasonic power at 120 W in a water bath, the extraction rate of germanium was 97.32 %. The extraction rate of zinc was 2.37 % under the conditions of a three-stage solid phase extraction column in series (single-stage filling N235 extraction resin 0.8 g), reaction temperature 25 °C, tartaric acid concentration of 2.0 g/L, and the dwell time is 4.1min. The saturated adsorption capacity of the resin is 51.90 mg/g. The extraction rate of germanium increased by 14.4 % under ultrasonic-assisted strengthening conditions. The [Ge(C4O6H4)3]2- can be separated from the resin by NaOH solution. The desorption rate of germanium was 94.12 % under the condition of water bath ultrasonic power of 120W, 30 ml concentration of 3.5 mol/L NaOH solution, and the dwell time is 5.2min. Under the optimum conditions, the extraction rate of N235 extraction resin was 85.23 % after repeated regeneration five times. The results demonstrate that the extraction resin exhibits high selectivity and reproducibility in complex systems, presenting a new method for extracting germanium under complex conditions.

Selective ion channel adsorbents facilitate efficient and low environmental impact extraction of liquid lithium resources

As lithium is the cornerstone of green energy development, it is crucial to realize a low environmental impact and efficient lithium extraction process. Ion-sieve adsorption is the most widely used method to extract liquid lithium resources, but this method is only efficient under alkaline conditions for H+ and Mg2+ competing adsorption. Conventional methods are often accompanied by the consumption of quantities of alkali, the generation of solid waste, and the acidification of liquid lithium resources. To address these issues, a selective ion-channel adsorbent was constructed. The composition comprises an ion sieve adsorbent and an organic carrier with a zwitterionic quaternary ammonium base group. This group storages OH- in situ, hinders H+ diffusion, slows down Mg2+ diffusion, and accelerates Li+ diffusion by relying on the difference in binding energies, which reduces the competing adsorption and avoids acidification and solid waste generation. The saturated adsorption capacity (21.38 mg/g) and selectivity of the adsorbent are 4.7 and 24 times higher than that of conventional ion-sieve adsorbent under neutral conditions respectively. The dosage of alkali is 1/256 of the traditional method, the effluent remains neutral and no solid waste is generated. This study presents an environmental and effective adsorbent for lithium extraction.

Task-Driven Tailored Covalent Organic Framework for Dynamic Capture of Trace Radioactive CH3 131I under High-Flow Rate Conditions.

The removal of radioactive gaseous iodine is crucial for sustainable nuclear energy development, safe spent fuel management, and secure disposal of radioactive waste and radioactive medical waste. However, the efficient capture of gaseous iodine, particularly methyl iodide, under conditions of low concentration and high-flow rate that are representative of real-world scenarios remains underexplored. Herein, we adopted a "theory-first" strategy to design adsorbents with a superior affinity for methyl iodide. The rigorous theoretical calculations for both physisorption and chemisorption have guided us to rationally design a piperazine-based covalent organic framework material (Pip-COF, Pip = piperazine). The pioneering hot-testing under dynamic conditions, featuring low concentrations of 5 ppm radioactive CH3 131I and a high-flow rate of 600 mL/min, demonstrated Pip-COF's exceptional capture performance. Pip-COF exhibits saturated capacities of 39 mg/g at 75 °C and 78 mg/g at 25 °C, significantly outperforming the previously reported best COF (COF-TAPT, 6 mg/g at 25 °C) in this scenario. The gradual process of methylation and the identification of specific high-affinity sites were elucidated by time-resolved FT-IR spectroscopy and density functional theory (DFT) analysis, consistent with the design philosophy. This study exemplifies rational material design in facilitating the separation of trace pollutants in challenging environments.

Study on the preparation of a novel acrylic modified magnetic chitosan adsorbent and the adsorption behavior on Ga (III)

In the current study, a novel acrylic modified magnetic chitosan adsorbent (M- AA −CTS) was prepared, and then characterized using SEM, FTIR, and XPS. The preparation conditions, adsorption conditions, adsorption kinetics and thermodynamics were also studied. FTIR results indicate that acrylic acid is grafted onto the amino groups of chitosan in the form of poly acrylic acid and the amino groups are also crosslinked with glutaraldehyde. For the preparation process, the removal efficiency of Ga (III) ions is higher when the amount of acrylic acid is 3 mL, the reaction temperature is 308 K, the crosslinking time is 80 min, and the amount of glutaraldehyde is 0.6 mL. During the adsorption process, the higher adsorption capacity of Ga (III) ions can be achieved under the condition of the initial concentration of Ga (III) ions 50 mg/L, the adsorbent dose 0.05 g, the oscillation temperature 308 K and pH 3. The study on the adsorption kinetic indicates that the adsorption follows the pseudo-second-order kinetic model. The study on isotherm adsorption and thermodynamic indicates that the adsorption isotherm fits the Langmuir isotherm model better and the saturated adsorption capacity of Ga (III) ions on M−CTS−AA can reach 183.09 mg/g. Study on desorption and regeneration shows that after four cycles of desorption and reuse, the regeneration rate decreased from the initial 91.47 % to 73.3 %.

Insights into the adsorption of emerging organic contaminant by low-cost readily separable modified jute fiber.

A high-efficiency biosorbent based on the low-priced jute fiber was developed, characterized, and applied to remove the emerging organic contaminant diclofenac from aqueous solutions. Jute fiber was treated by NaOH (named AJF) followed by graftingdifferent amounts of trimethyl[3-(trimethoxysilyl) propyl] ammonium chloride (named AJF-TTSAC). The composition, morphology, porosity, and adsorption features of the neat and modified jute fiber were evaluated and compared. The surface of neat JF was smooth, nonporous, and free of cracks. NaOH treatment increased the fibrillation, created cracks and grooves, and increased the oxygen content, total pore volume, and surface area. In comparison to AJF, grafting TTSAC filled in the crevices, grooves, and spaces between fibrillates, and decreased the total pore volume and surface area. The adsorption of diclofenac by the neat and modified JF occurred at highly acidic pHo and peaked at pHo 3. Among the neat and modified JF, AJF-TTSAC5 was the most efficient followed by AJF. The efficiency of AJF and AJF-TTSAC5 was highest using 1.00 g/L, at 35 °C and was not affected by the presence of NaCl. The Elovich, pseudo-first-order, and pseudo-second-order models described the adsorption kinetic satisfactorily with the marginal advantage of Elovich for AJF and pseudo-second-order for AJF-TTSAC5. The isotherm study exposed the multilayer and physisorption nature of the adsorption of diclofenac onto AJF and AJF-TTSAC5. The Langmuir monolayer saturation capacity of AJF-TTSAC5 was 37.43 mg/g which revealed its great potential relative to other adsorbents in the literature. The AJF and AJF-TTSAC5 were easily regenerated using distilled water and kept good performance for 5 repetitive cycles.

Artificial Grassland Revegetation Improves Soil Water Retention and Storage Capacity of the Degraded Hillside Alpine Meadow

ABSTRACTThe crucial role of soil water retention and storage in soil hydrology and the water cycle is well established. However, in sensitive and degraded ecosystems like alpine meadows, the effectiveness of revegetation in enhancing these critical functions remains understudied. This study investigates the effects of revegetating severely degraded hillside meadows with artificial grasslands on soil water retention and storage capacity in the Qinghai‐Tibetan Plateau. Soil analyses at a depth of 0–20 cm revealed significant improvements in soil properties after revegetation, with increases in soil organic matter content (86.8%), total porosity (11.9%), capillary porosity (31.6%), and clay content (13.5%). Both the saturated hydraulic conductivity (Ks) and field capacity (FC) increased markedly, by 9.7% and 63.7% in the upper layer (0–10 cm) and 21.7% and 69.6% in the lower layer (10–20 cm), respectively. Structural equation modeling identified bulk density, root mass density, FC, capillary porosity, and clay content as the dominant direct factors influencing Ks with path coefficients of −0.56, 0.30, −0.53, 0.57, and −0.12, respectively, while vegetation cover and aboveground biomass were found to have indirect influences. These findings demonstrate that revegetation with artificial grasslands effectively improves soil water retention and storage capacity in degraded hillside alpine meadows by regulating key soil hydraulic and physical properties. This enhanced water‐holding capacity has significant implications for understanding the dynamics of revegetation by artificial grassland establishment in improving ecosystem health and eco‐hydrological functions in these vulnerable environments. Furthermore, the study provides valuable insights and a theoretical basis for developing ecological restoration solutions for degraded hillside meadows in other alpine regions.

Preparation of artificial humic acid from corn straw and its high-efficiency adsorption on norfloxacin

In this study, the biomass artificial humic acid (AHA) with efficient adsorption performance for norfloxacin (NOR) was prepared by ultrasonic-assisted acid-alkaline combined hydrothermal method with corn straw as raw material. Characterization analysis showed that AHA was a typical amorphous structure, and the oxygen content of AHA prepared by ultrasonic-assisted hydrothermal method was obviously improved compared with that without ultrasonic-assisted method. The saturated adsorption capacity of AHA was 551.53 mg/g, which was higher than that of other reported materials, such high-efficiency adsorption is due to the abundant oxygen-containing groups (–OH, –C=O, etc.) in AHA, which were functional groups that can be π-π stacked, hydrogen bonded and electrostatically bonded with NOR. It had good selective adsorption for NOR, with less interference from acidity of environmental water, coexisting inorganic ions and common antibiotics. When it was applied to adsorb NOR with concentration of 10.0 mg/L in simulated water prepared by environmental water, the highest removal rate was 91%, which indicated that AHA could not only remove all the NOR in the polluted water with complex components at the highest concentration of 630 μg/L, but also its adsorption capacity far exceeded the pollution amount. The research had important practical significance in realizing the recycling of agricultural wastes and the removal of environmental pollution.

Preparation of a Porous Spherical Adsorbent by Oil-In-Water-In-Oil Emulsion Polymerization for Phycocyanin Adsorption

ABSTRACT Phycocyanin is a protein with potential in food and medical applications. A porous spherical adsorbent was prepared by oil-in-water-in-oil emulsion polymerization. Oil and water phases containing surfactants and monomers, respectively, were emulsified, and the prepared emulsion was added to the oil phase to polymerize the porous spherical adsorbent. The concentration ratio of N,N-dimethylacrylamide and 2-dimethylaminoethylmethacrylate (DMAEMA) in the water phase was changed. The obtained spherical adsorbent had a size of about 150 μm and a water content of 90%, with macropores of several micrometers. Phycocyanin (20 kDa) of Nostoc commune was leached by the freeze and thaw method to prepare the solution. The adsorption data of the batch and column modes were evaluated by ordinary differential and partial differential equations, respectively, considering competitive adsorption, to obtain parameters of the mass transfer coefficient and saturated adsorption capacity. In the b\ sfer coefficient of phycocyanin decreased by about one-third, but the saturated adsorption capacity increased three-fold. In the continuous flow column, leached biomacromolecules other than phycocyanin had greater parameters of mass transfer and capacity. To prepare an adsorbent for the biomacromolecules, selective adsorption sites in the polymer matrix should be designed and prepared.

Eliminating the effect of pH: Dual-matrix modulation adsorbent enables efficient lithium extraction from concentrated seawater

Lithium ion sieve adsorbents frequently extract liquid lithium resources due to their adsorption effect and cost advantages. However, the adsorption effect is significantly influenced by the ambient pH. The pH effects on the adsorption process can be categorized into two main areas: the competition adsorption of impurity ions and the difference in surface zeta potential. A dual-matrix modulation adsorbent was prepared, comprising a carrier matrix modified with zwitterionic quaternary ammonium bases and an adsorption matrix modified with carboxylation. The zwitterionic quaternary ammonium base groups were employed to mitigate the competitive adsorption of impurity ions by acid-base neutralization. Furthermore, the negative charge of carboxyl groups was employed to diminish the discrepancy in surface zeta potential. The adsorption effect of the ion sieve adsorbent under natural conditions appeared to be significantly enhanced by the dual-matrix modulation, with the saturated adsorption capacity (28 mg/g) and adsorption selectivity (α(Li+/Mg2+)=24.23) being 6.3 and 7.8 times higher than that of the manganese-based adsorbent (HMO) under the same conditions, respectively. Moreover, the adsorption effect was found to be consistent with HMO under alkaline conditions. The results demonstrate that by optimizing the adsorption conditions of the adsorbent, the detrimental impact of pH on the adsorption process of lithium ion sieves can be eliminated.

Metal Ions Modified Azo‐Linked Porous Polymers for High Performance CO2 Capture

AbstractPorous polymer show great potential for CO2 capture owing to its high specific surface area, adjustable porous structure and chemical structure. Herein, a novel CO2 adsorption materials ALP−M (M: Cu2+, Mg2+, Ni2+) were prepared through coordination between azo‐linked porous polymer (ALP) synthesized by oxidative coupling polymerization of tris(4‐aminophenyl)amine and metal ions. The structures and morphology of as‐prepared materials were demonstrated by FT‐IR, XRD, XPS, BET and SEM, the CO2 capture performance and mechanism of ALP−M were also investigated through static adsorption and column adsorption experments, the results show that metal ions can enhance the CO2 adsorption and desorption performance of ALPs by coordination adsorption. ALP−M showed a highest static CO2 adsorption capacity of 2.67 mmol g−1 at 273 K (1 bar), which is 35.5 % higher than that of ALP. The metal ions served as Lewis acid sites can enhance the affinity of adsorbent for CO2. In column adsorption experiments, the ALP−M showed a higher saturated adsorption capacity 4.99 mmol g−1 at 273 K (1 bar) than that of static adsorption, and excellent cycling stability after 500 adsorption and desorption cycles, the adsorption capacity retention rate of ALP−M for CO2 can reach 98 %.