An aminated chelating fiber (AF) with high adsorption capacity for mercury ions was prepared by grafting copolymerization of acrylonitrile onto polypropylene fiber, followed by aminating with ...chelating molecule diethylenetriamine. Effects of reaction conditions such as temperature, reaction time, bath ratio and dosage of catalyst on the grafting yield were studied. Chemical structure, tensile strength and thermal stability of AF were characterized. The adsorption performances for mercury were evaluated by batch adsorption experiments and kinetic experiments. The results show that AF is effective for the removal of mercury over a wide range of pH. The chelating fiber also shows much higher adsorption capacities for mercury, the equilibrium adsorption amount could be as high as 657.9
mg/g for mercury. The high adsorption capacity of Hg
2+ on AF is resulted from the strong chelating interaction between amine groups and mercury ions. Two amine groups coordinate with one mercury ion could be speculated from the adsorption capacity and amine group content on AF. The kinetic adsorption results indicate that the adsorption rates of AF for mercury are very rapid. Furthermore, the residual concentration was less than 1
μg/L with feed concentration of mercury below 1
mg/L, which can meet the criterion of drinking water, which indicates that the chelating fiber prepared in this study could be applied to low-level Hg contaminated drinking water purification.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Reducing nitrogen loss during composting with forced ventilation was comprehensively investigated in this study. Coral sand was tailored in the co-composting in the co-composting of sludge and ...litters. The physicochemical results revealed that forced ventilation prolonged the thermophilic phase and accelerated the substrate decomposition. With the addition of 10% native coral sand, the amount of nitrogen loss decreased by 9.2% compared with the original group. The microbial community evaluation revealed that the effect of forced ventilation on colony abundance was significantly greater than that of adding coral sand. This study demonstrated that when composting on a tropical island, adding coral sand under forced ventilation was a viable solution for realizing sustainable development.
Camellia oleifera fruit shell (COS) is an agricultural waste product generated in large quantities by the seed oil extraction industry. Due to its hierarchical thickness structure, COS shows huge ...potential in constructing porous carbon materials after thermal chemical modification. Herein, a series of COS biochars were synthesized by a carbonization-activation process and achieved excellent mercury removal performance in an aqueous environment. High-temperature carbonization was found to facilitate lignin removal and porosity generation, while retaining hydroxyl and carbonyl groups available for mercury adsorption. A volume of micropores of 594 × 10−3 cm−3/g with average pore diameter of 1.7 nm was achieved in activated COS biochar. At 550 °C, an adsorption capacity of 57.6 mg/g was realized in 1 mg/L Hg2+ solution under different pH environments. This work provides an alternative adsorbent for removing hazardous materials using sustainable bioresources.
The effect of steam explosion pretreatment conditions, such as steam explosion pressure, maintained pressure time, and bagasse water content, on bagasse specific surface area were investigated ...through single-factor experiments. After determining the optimal pretreatment conditions, bagasse graft acrylamide was prepared by grafting polymerization reaction of the acrylamide monomer onto the pretreated bagasse. The effects of surface area on the grafting degree were analyzed. Results showed that the grafting degree increased with increasing specific surface area. The optimized steam explosion pretreatment conditions were as follows: steam explosion pressure, 2.0 MPa; pressure maintaining time, 60 s; and bagasse water content, 25%.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
A thermosensitive solid amine fiber SF-AM-co-NIPAM-HBP-NH2 was synthesized by grafting temperature-sensitive monomer N-isopropyl acrylamide (NIPAM) as well as acrylamide (AM) onto the surface of ...substrate sisal fiber, and further aminating with hyperbranched amine. FTIR, 13C NMR, SEM, EA and TGA were used to confirm the structure and chemical properties of the grafted fibers. Swelling ratio and CO2 adsorption-desorption experiment were investigated to verify the thermo-sensitivity of the grafted fibers and their CO2 adsorption-desorption behavior. Compared with conventional solid amine adsorbents regenerated around 140 °C, SF-AM-co-NIPAM-HBP-NH2 (1:1) with NIPAM could be regenerated at a much lower temperature of 60 °C, while still maintain a high CO2 adsorption capacity (2.61 mmol/g), comparable to that of SF-AM-HBP-NH2 (2.73 mmol/g) before NIPAM introduction. Its excellent regeneration property and the effect of energy consumption reduction make it possible to be used for CO2 adsorption in industrial process.
•Biomass fiber was used as a renewable substrate for CO2 adsorbent preparation.•The adsorbent could have high CO2 adsorption capacity by amination.•The adsorbent showed obvious thermosensitive property, owing to the introduction of NIPAM.•The absorbent could be regenerated at 60 °C, much lower than 140 °C of conventional solid amine adsorbents.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
An aminated bagasse (AB) with high-adsorption capacity for mercury ions was prepared by grafting copolymerization of acrylonitrile onto sugarcane bagasse, followed by aminating with chelating ...molecule diethylenetriamine. Effects of grafting conditions such as irradiation dosage, acrylonitrile concentration, and solvents on the grafting yield were investigated. The adsorption performance for mercury ions were evaluated by batch adsorption experiments and kinetic experiments. The results show that AB is effective for the removal of mercury over a wide range of pH > 5. Adsorption isotherms of mercury ions on the modified bagasse can be well described by Langmuir equation. The equilibrium adsorption amount could be as high as 917.4 mg/g, and the removal percent of mercury ions can achieve 99%. The kinetic adsorption results indicate that AB could remove 80% of mercury ions in 2 h and 24 more hours are needed to achieve adsorption equilibrium. Regeneration experiments show that the adsorption capacity of recycled AB still can reach the level of 96% after four cycles.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
•A hierarchically porous carbon functionalized with Fe-Mn oxide was fabricated for superior removal of Hg(II) from water.•The composite exhibits high adsorption efficiency of 96.8% and fast ...adsorption rate for the removal of Hg(II).•The high efficiency is contributed by the synergy between physical and chemical adsorption.•The adsorption kinetics agrees with the pseudo-second order model, and isotherms are consistent with the Freundlich model.
The removal of heavy metal ions from industrial wastewater by adsorption has been central to the environment for decades, where common adsorbent materials are often limited by poor efficiency, complex fabrication and long processing time. Porous carbon derived from biospecies holds promise to address the limitations. In this study we converted bagasse into a carbon composite having hierarchically porous structure; the composite’s dispersion phases – iron oxide and manganese oxide – were synthesized by a simple one-step liquid-phase reaction method. Featuring large specific surface area of 350.8 m2 g−1, the composite demonstrated exceptional Hg (II) removal efficiency of 96.8%, adsorption rate of up to 96.8% within 150 min and adsorption capacity of 9.8 mg g−1. In comparison with other removal materials, our work is outstanding in terms of both removal efficiency and synthesis simplicity. The high efficiency is attributed to the synergy between physical adsorption referring to hierarchically porous structure and chemical adsorption relating to functional complexation processes. It provides a new avenue for the development of high-performance adsorbent materials for heavy metal removal from aqueous media.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Functional tissue engineered heart valves (TEHV) have been an elusive goal for nearly 30 years. Among the persistent challenges are the requirements for engineered valve leaflets that possess ...nonlinear elastic tissue biomechanical properties, support quiescent fibroblast phenotype, and resist osteogenic differentiation. Nanocellulose is an attractive tunable biological material that has not been employed to this application. In this study, we fabricated a series of photocrosslinkable composite hydrogels mNCC‐MeGel (mNG) by conjugating TEMPO‐modified nanocrystalline cellulose (mNCC) onto the backbone of methacrylated gelatin (MeGel). Their structures were characterized by FTIR, 1HNMR and uniaxial compression testing. Human adipose‐derived mesenchymal stem cells (HADMSC) were encapsulated within the material and evaluated for valve interstitial cell phenotypes over 14 days culture in both normal and osteogenic media. Compared to the MeGel control group, the HADMSC encapsulated within mNG showed decreased alpha smooth muscle actin (αSMA) expression and increased vimentin and aggrecan expression, suggesting the material supports a quiescent fibroblastic phenotype. Under osteogenic media conditions, HADMSC within mNG hydrogels showed lower expression of osteogenic genes, including Runx2 and osteocalcin, indicating resistance toward calcification. As a proof of principle, the mNG hydrogel, combined with a viscosity enhancing agent, was used to 3D bioprint a tall, self‐standing tubular structure that sustained cell viability. Together, these results identify mNG as an attractive biomaterial for TEHV applications.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
A novel chelating fiber was prepared by the irradiation-induced grafting copolymerization of glycidyl methacrylate on polypropylene fiber and consequent amination with diethylenetriamine. The effects ...of the reaction conditions, such as reaction time, temperature, and monomer concentration, on the degree of grafting were investigated. The optimal conditions for grafting were found to be 3 h, 100°C, and a 50% (v/v) glycidyl methacrylate concentration in tetrahydrofuran solution. This fiber showed good adsorption performance at different concentrations of Hg²⁺, in particular for trace Hg²⁺. Under the adsorption conditions of pH = 4, initial concentration = 1000 mg/L, and time = 20 h, the adsorption capacity of the chelating fiber for Hg²⁺ reached 785.28 mg/g. It completely adsorbed the Hg²⁺ ions in solution within a short contact time, showing a very high adsorption rate for Hg²⁺. Furthermore, the chelating fiber also had a high selectivity for mercury, whereas Cu²⁺ coexisted in different concentrations.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
A novel porous solid amine adsorbent (PEI@polyHIPE) with a highly interconnected pore network was prepared by high inner phase emulsion (HIPE) polymerization of styrene and divinylbenzene, and was ...simultaneously functionalized with high molecular weight (Mw = 70 000 Da) polyethylenimine (PEI). This proposed route requires fewer chemical reagents and less energy than conventional solid amine adsorbents that were prepared by amine post-modification such as chemical grafting and wet impregnation. The SEM image shows that a PEI layer was formed on the adsorbent's surface without damaging its original structure. And the CO2 adsorption capacity and pore structure of PEI@polyHIPE could be adjusted by adding different amounts of PEI. The one-step fabricated 4.0PEI70k@polyHIPE adsorbent showed a maximum adsorption capacity of 4.18 mmol CO2 per g-adsorbent at 20 °C under humid conditions. It obviously exhibited better CO2 adsorption performance, high amino utilization efficiency, and quick adsorption kinetics compared to PEI post-modification porous polystyrene (polyHIPE-PEI). This was attributed to its well-interconnected hierarchical structure, which could remarkably reduce gas diffusion resistance. Meanwhile, owing to the high-molecular-weight of PEI, the amount of amine loss could decrease during the process of adsorption/desorption, thus the adsorbent of PEI@polyHIPE showed promising regeneration performance. This one-step synthetic route provides a novel strategy for preparing amine functionalized adsorbents with high sorption capacity, amine efficiency, and regeneration stability.
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