Search

The directed construction of productive adsorbents is essential to avoid damaging human health from the harmful radioactive and toxic U(VI)-containing wastewater. Herein, a sort of Zr-based metal organic framework (MOF) called PCN-222 was synthesized and oxime functionalized based on directed molecular structure design to synthesize an efficient adsorbent with antimicrobial activity, named PCN-222-OM, for recovering U(VI) from wastewater. PCN-222-OM unfolded splendid adsorption capacity (403.4 mg·g−1) at pH = 6.0 because of abundant holey structure and mighty chelation for oxime groups with U(VI) ions. PCN-222-OM also exhibited outstanding selectivity and reusability during the adsorption. The XPS spectra authenticated the -NH and oxime groups which revealed a momentous function. Concurrently, PCN-222-OM also possessed good antimicrobial activity, antibiofouling activity, and environmental safety; adequately decreased detrimental repercussions about bacteria and Halamphora on adsorption capacity; and met non-toxic and non-hazardous requirements for the application. The splendid antimicrobial activity and antibiofouling activity perhaps arose from the Zr6(μ3-O)4(μ3-OH)4(H2O)4(OH)4 clusters and rich functional groups within PCN-222-OM. Originally proposed PCN-222-OM was one potentially propitious material to recover U(VI) in wastewater on account of outstanding adsorption capacity, antimicrobial activity, antibiofouling activity, and environmental safety, meanwhile providing a newfangled conception on the construction of peculiar efficient adsorbent. [ABSTRACT FROM AUTHOR]

The ever-increasing carbon emission requires the development of advanced carbon capture and storage technology. As one of the most promising approaches, the adsorption of CO 2 over porous carbon (PC) has been intensively studied due to the low cost, easy synthesis, and high adsorption capacity of PC. However, further improvement in its CO 2 adsorption capacity is hindered by the unclear relationship between each physicochemical property and the adsorption capacity. Recently machine learning (ML) has achieved giant progress in predicting the adsorption capacity of PCs. However, due to the intrinsic "black box" property of ML, the quantitative relationship between each physicochemical property and corresponding adsorption capacity cannot be derived. Herein, first random forest was well trained to predict the CO 2 adsorption capacity. Then, Shapley Additive Explanations, a powerful visualization tool, was adopted to provide insights into such an uncovered relationship. The results showed that textural property is more important than chemical composition in affecting CO 2 uptake. Furthermore, SHAP indicated that high CO 2 adsorption capacity appeared at low pressure, temperature of 298 K with specific surface area of 1100–1300 m2/g, micropore volume of 0.4–0.6 cm3/g, mesopore volume of < 0.1 cm2/g, carbon of 72–86 wt%, hydrogen of 1–4 wt%, oxygen of < 16 wt%, and nitrogen of < 1 wt%. This study sheds light on the understanding of the CO 2 adsorption mechanism on PC and guides the design of next-generation high-performance PC for carbon capture and storage. • Four different machine learning models were trained for predicting CO 2 adsorption capacity of porous carbon. • Random Forest model shows the best predication accuracy than others do. • Shapley Additive Explanations was used to elucidate the structure-performance relationship. • The desired physicochemical parameter of porous carbons for achieving high CO 2 adsorption is presented. [ABSTRACT FROM AUTHOR]

Surface molecularly imprinting polymer (SMIP) was utilized in the removal of a residual pesticide (carbaryl (CBL)) in water and simulated fruit juice. Being the crosslinking agent, ethylene glycol dimethacrylate (EGDMA) was copolymerized with the monomer, methacrylic acid (MAA) and CBL as the template molecules on the surface of the silica gel particles to produce the SMIP adsorbents. The SMIP adsorbents showed good selectivity and good adsorption capacity for CBL in the competitive adsorptions with two structurally related carbamate pesticides. The effect of the pretreatment solvents on the adsorption capacity of the SMIP adsorbent was investigated with the results of the numerical simulations. The adsorption isotherms and the adsorption kinetics were well described by the Freundlich equilibrium model and the pseudo-second-order kinetic model, respectively. Scatchard plot analysis revealed that there were two classes of binding sites populated in the SMIP adsorbents. In addition, the good selective adsorption of CBL by the SMIP adsorbent in a simulated fruit juice containing vitamin C and fructose indicated the great potential of the SMIP adsorbents to remove residual pesticide in food industry and processing industry for agricultural products. [ABSTRACT FROM AUTHOR]

The extraction of U(VI) ions from aqueous solution was considered as a difficult task in the industry. In this study, a phosphate-modified metal-organic framework (PCN-224-HEDP) was designed and synthesized for efficient U(IV) adsorption via a common postsynthetic method of PCN-224 grafting hydroxyethylidene diphosphonic acid. [Display omitted] The extraction of U(VI) ions from aqueous solution was considered as a difficult task in the industry. In this study, a phosphate-modified metal-organic framework (PCN-224-HEDP) was designed and synthesized for efficient U(IV) adsorption via a common postsynthetic method of PCN-224 grafting hydroxyethylidene diphosphonic acid. The results of TEM, XPS, FT-IR, XRD and BET indicated the PCN-224-HEDP possessed regular cubic structure, high specific surface area and abundant phosphate functional groups. PCN-224-HEDP exhibited more excellent adsorption capacity for U (VI) than that of PCN-224. Besides, the adsorbent also exhibited great selectivity and recyclability of uranium adsorption. Furthermore, the uranium adsorption process of PCN-224-HEDP was in the control of chemical and monolayer adsorption, and the XPS spectra confirmed that the phosphate groups played a important role in the adsorption process. All results indicated that PCN-224-HEDP was an efficient adsorbent for U(VI) extraction from aqueous solutions. [ABSTRACT FROM AUTHOR]

In this study, carboxylated graphene oxide (GO-COOH) was prepared via a simple and feasible method to enhance the adsorption of U(VI). GO-COOH were characterized by FT-IR, XRD and XPS technique, and then applied as the adsorbent for U(VI) ions removal from water. The effects of conditions for U(VI) adsorption, including initial pH of aqueous solution, adsorbent dose, contact time, and initial concentration of U(VI) solution were investigated. The result indicated that the maximum adsorption of U(VI) on GO-COOH was 315 mg/g at the optimum adsorption condition (C a = 0.2 g/L, pH = 6.0, t = 6 h, C 0 = 100 mg/L and T = 25 °C), which was significantly higher than that on GO (190 mg/g) in the same condition. Compared to GO, the maximum U(VI) adsorption capacity of GO-COOH increases by 65.8%. The adsorption process was described well with pseudo-second-order kinetics and the Langmuir isotherm model, indicating the chemisorption process and monolayer adsorption process. GO-COOH with increased carboxyl group content and expanded interface distance was successfully prepared from GO via a facile method. GO-COOH showed the enhanced adsorption of U(VI) compared to GO. Adsorption process was mainly dominated by chemisorption and monolayer adsorption. Image 1 • GO-COOH with increased carboxyl group content and expanded interface distance was prepared from GO via a facile method. • GO-COOH showed obviously higher adsorption capacity of U(VI) than GO. • The adsorption process for U(VI) was mainly dominated by chemisorption and monolayer adsorption. [ABSTRACT FROM AUTHOR]

[Display omitted] • Easily treated organic porous hyper-cross-linked polymers and big BET surface area. • A novel phosphate esterification hyper-cross-linked polymer was prepared. • PHCP-BF has a maximum sorption capacity of 120 mg/g. • High selective and good regeneration of PHCP-BF. There is a strong need for the development of effective uranium sorbents. Here, the Friedel-Crafts reaction was performed in a simple one-step manner followed by phosphate esterification to prepare porous hyper-cross-linked Bisphenol F (PHCP-BF) for prospective utilization in the removal of U(VI) from wastewater. PHCP-BF has pores with a size of 2.6 nm and a significant BET surface area (up to 387.31 m2/g). It was extensively investigated how a variety of environmental conditions (e.g., pH, contact time, temperature, etc.) affected the treatment results. In terms of adsorption capacity, uranium possessed a maximum of 120 mg/g (pH = 7), which is twice that of the original material HCP-BF (59.39 mg/g). According to the modeling results, with the Langmuir isotherm and a pseudo-second-order kinetic model, the data matched the sorption data very well. It was found that PHCP-BF possessed good selectivity for uranium, which was considerably greater than that of other co-existing metals. After three cycles, PHCP-BF still maintained a certain adsorption capacity. In light of several spectroscopic examinations, the mechanism of uranium removal by PHCP-BF is the chelated of P = O with U (VI). The results obtained suggest that PHCP-BF can be used effectively to remove uranium from water. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel amidoxime functionalized hyper-cross-linked fluorene-9-bisphenol was prepared. • HCP-AO have a maximum sorption capacity of 234.46 mg/g. • Equilibrium can be reached within 240 min. • In the solution containing competing metal ions, HCP-AO is selective for U (VI). Pollution, such as uranium(U), resulting from radionuclides, has become a severe environmental problem. Hence, developing highly efficient materials to reduce the environmental influence of uranium is necessary. Here, amidoxime functionalized hyper-cross-linked fluorene-9-bisphenol (HCP-AO) was synthesized by a Friedel–Crafts reaction followed by an amidoxime functionalization as a novel uranium adsorbent. The sorption properties of HCP-AO for U (VI) from water were evaluated in various environmental conditions (e.g., solution pH, contact time, temperature, etc.). The HCP-AO was characterized by a series of characterization methods. The HCP-AO's maximum U(VI) sorption capacity was 234.46 mg/g (pH = 7) due to the strong coordination of amidoxime groups (AO) with uranium. The sorption data well matched with Langmuir isotherm and the pseudo-second-order kinetic model. Even with competing metal ions, HCP-AO exhibited selective uranium adsorption capacity. After three regeneration cycles, the HCP-AO's adsorption capacity was still considerable. These findings indicated that HCP-AO could be used to extract uranium from uranium-bearing wastewater. [ABSTRACT FROM AUTHOR]

• Synthesis of a novel U (VI) adsorbent HCP-Phenylalaninol (HCP-PAO), a porous hypercrosslinked aminol. • The hypercrosslinked product is simple to synthesize and shows porosity, large surface area and good thermodynamic stability properties. • HCP-PAO shows efficient U (VI) adsorption performance (Q e = 369.5 mg/g, pH = 7) and long service life. • HCP-PAO shows good selective toward uranium at simulated seawater. Uranium mining from seawater has sparked a lot of research curiosity. Here, we synthesized a porous hypercrosslinked phenylalaninol (HCP-PAO) for U (VI) adsorption from water, in which phenylalaninol bearing amino and hydroxyl groups was used as the monomer, and biphenyl dichlorobenzyl (BCMP) was used as the external crosslinker. The resulting porous adsorbent has a surface area of 562.6 m2/g and a pore volume of 0.41 cm3·g−1. The pore size distribution is focused around 3–4 nm, indicating that it is a typical mesoporous polymer. The adsorbent had the most promising adsorption performance at pH = 7, reaching adsorption saturation in a 100-ppm uranium-doped solution for 2 h (adsorption capacity of 369.5 mg/g). HCP-PAO was particularly sensitive to uranium in complicated settings (56.3 % removal rate), and the adsorption mechanism closely resembled the Langmuir model and the pseudo-second-order model well. The practically consistent adsorption capacity of the HCP-PAO after five adsorption/resolution studies indicated its high recyclability. The mechanism of uranium extraction by HCP-PAO is the synergistic coordination of –NH 2 and –OH with U (VI). HCP-PAO had an adsorption capacity higher than 100 mg/g at pH = 8 which is close to the pH of natural seawater, and showed good selectivity for U (VI) in simulated seawater experiments (removal rate over 55 %). Our research suggests that the novel hypercrosslinked product HCP-PAO can be applied as an adsorbent to efficiently capture U (VI) from water, and also it has great potential in seawater uranium extraction as well as expanding the research concept of porous uranium adsorbent. [ABSTRACT FROM AUTHOR]

Herein, a novel amidoxime functionalized metal organic framework (MOF)-based adsorbent named PCN-222-AO was obtained by grafting amidoxime groups on the surface of PCN-222 through amination, cyanylation and amidoximation modification reactions successively. The PCN-222-AO exhibited outstanding adsorption capacity (432.7 mg·g−1), selectivity and reusability in U(VI) adsorption at pH = 7.0, and showed superb adsorption performances in the simulated and real seawater. The XPS spectra and adsorption energy calculations confirmed the C N (H 2 TCPP), C=N-OH and -NH (2) groups served a vital role in the U(VI) adsorption process. PCN-222-AO illustrated excellent antibacterial property, anti-biofouling activity and environmental safety, which effectively reduced the negative impacts of bacteria (E. coli and S. aureus) and Halamphora upon the U(VI) adsorption capacity and complied with the requirements for non-toxicity and innocuousness in the adsorbent application. The excellent antibacterial property and anti-biofouling activity may be attributed to Zr 6 cluster and abundant functional groups in the PCN-222-AO. Undoubtedly, the molecular structure design and construction of effective adsorbents are crucial for the U(VI) resource recovery. As first reported in this study, PCN-222-AO is a promising adsorbent to recover U(VI) from seawater, providing a new idea about the molecular structure design and construction of novel high-efficiency adsorbent. [Display omitted] • Novel adsorbent named PCN-222-AO was synthesized based on molecular structure design. • PCN-222-AO exhibited distinguished antibacterial activity and recycling ability. • PCN-222-AO showed excellent U(VI) adsorption capacity, Q e reached 432.7 mg·g−1. • Mechanism was the co-effect of coordination and electrostatic interaction. • The adsorbent possessed great potential to efficiently recover U(VI) from seawater. [ABSTRACT FROM AUTHOR]

In this study, a novel amidoxime functionalized graphene oxide adsorbent (GO-D-AO), based on the reaction of dopamine modified graphene oxide with acrylamide diacetonitrile and on the reaction of amidoximation, was successfully designed and prepared to effectively adsorb U(VI) ions. GO-D-AO was characterized by SEM, FT-IR, XRD and XPS techniques, and then applied as the adsorbent for the U(VI) adsorption. The GO-D-AO contained more amidoximation groups after the amidoximation modification due to the use of acrylamide diacetonitrile modifier. A series of adsorption experiments were carried out to investigate the influence factors in the adsorption process, including the pH values, contact time, temperature and initial concentration of U(VI) solution. The U(VI) maximum adsorption capacity of GO-D-AO was 1823.6 mg·g -1 , which was significantly higher than that of GO because of the excellent chelating ability of amidoxime group with U(VI) ions. And the U(VI) adsorption process of GO-D-AO fitted well with the Langmuir model and the pseudo-second-order kinetic model, indicating the adsorption process was monolayer and chemical adsorption. [Display omitted] • A highly efficient U(VI) adsorbent named GO-D-AO was designed and synthesized. • GO-D-AO contained abundant AO groups due to the use of acrylamide diacetonitrile. • GO-D-AO showed excellent adsorption capacity, Q max reached 1823.6 mg g−1 at pH = 7. • The adsorption process was dominated by chemisorption and monolayer adsorption. [ABSTRACT FROM AUTHOR]

[Display omitted] • Amino acids were grafted onto MIL-101 to produce novel uranium adsorbents. • Histidine-modified MIL-101 shows the highest U(VI) adsorption capacity of 345 mg·g−1. • Imidazole and carboxyl group and large specific surface area play important role. Three novel uranium adsorbents were synthesized by modifying MIL-101 with three amino acids: glycine, histidine and cysteine. The BET (Brunauer-Emmett-Teller) specific surface areas of amino acid modified MIL-101 (MIL-101-Gly, MIL-101-His and MIL-101-Cys) are 429 m2∙g−1, 713 m2∙g−1 and 104 m2∙g−1, respectively, indicating that the modified MIL-101 retained high specific surface area. All the modified MIL-101 s showed good uranium adsorption performance, in which the uranium adsorption performance of MIL-101-His is the best that can reach 345 mg·g−1 at pH = 6. The adsorption process of three amino acid modified MIL-101 s all accord with Langmuir and pseudo-second-order model for monolayer chemical adsorption. In the existence of K, Ca, Na, Sr, Ba, Cd, Co and Pb, the uranium (VI) removal rate of MIL-101-His can reach 74% indicating its excellent selectivity. After five adsorption–desorption cycles, the adsorption capacity of MIL-101-His still remains good capacity of 300 mg·g−1. In short, we prepared three novel amino acid modified MIL-101 s, and the histidine modified MIL-101 showed the best uranium adsorption performance, including adsorption capacity, selectivity and recyclability. [ABSTRACT FROM AUTHOR]

[Display omitted] • A porous Ag+ decorated PCN-222@graphene oxide-chitosan foam adsorbent was developed. • The adsorbent exhibited the excellent macrostructure and antibacterial property. • The adsorbent showed high U(VI) adsorption capacity, Q e reached 348.8 mg/g. • Mechanisms were coordination, electrostatic interaction and intraparticle diffusion. • The adsorbent possessed great potential to efficiently recover U(VI) from seawater. In this study, a 3D porous Ag+ decorated PCN-222 @ graphene oxide-chitosan foam adsorbent (APGC foam), which is grounded upon the growth of Ag+ decorated zirconium-metalloporphyrin metal–organic framework (PCN-222) on an EDTA-silane modified graphene oxide-chitosan foam substrate (EGC foam) for recovering U(VI) ions out of the seawater, was designed and synthesized with the in-situ growth and solvothermal method. The successfully synthesized APGC foam with excellent antibacterial property not only overcame the difficulty of powder adsorbents in practical application, but also reduced the negative impact of bacteria on the adsorption performance of porous material. The APGC foam showed excellent adsorption capacity (348.8 mg/g), selectivity and reusability of U(VI) adsorption at nearly seawater pH, and this also exhibited excellent adsorption performances in the seawater. The influence factors in the adsorption process were investigated by static and dynamic adsorption in different conditions. Moreover, the U(VI) adsorption mechanism of APGC foam was determined as the comprehensive effect of coordination, electrostatic interaction and intraparticle diffusion. All results indicated that APGC foam was an encouraging adsorbent to recover U(VI) out of the seawater. [ABSTRACT FROM AUTHOR]

Herein, a dual-function Zeolitic Imidazole Frameworks (ZIFs) ZIF-90 grafted with malononitrile by Knoevenagel reaction and following with an amidoximation reaction to form an efficient U (VI) adsorbent (ZIF-90-AO). The strong chelation power of amidoxime groups (AO) with uranium and ZIF-90 's mesoporous structure afforded ZIF-90-AO high maximum uranium adsorption capacity of 468.3 mg/g (pH = 5). In addition, the factors affecting uranium adsorption process were investigated by a batch of adsorption tests under different adsorption conditions. ZIF-90-AO displayed good selectivity to UO 2 2+ in the solution containing multiple co-existing ions and good regeneration property. More importantly, ZIF-90-AO showed excellent antimicrobial property against both E. coli and S. aureus. Therefore, ZIF-90-AO is a U-adsorbent with great application value for removing U (VI) from wastewater due to the high U (VI) adsorption capacity in weak acid condition and good anti-biofouling properties. [Display omitted] • A novel U (VI) adsorbent ZIF-90-AO with good anti-fouling performance is prepared. • The maximum U (VI) adsorption capacity of ZIF-90-AO (468.3 mg/g) is much higher than ZIF-90 at pH = 5. • The MICs of ZIF-90-AO against E. coli and S. aureus are 250 and 62.5 mg/L, respectively. • Perspectives about the adsorbent (ZIF-90-AO) for the removal of U (VI) from wastewater are presented. [ABSTRACT FROM AUTHOR]

[Display omitted] • • ZIF-90 and ZIF-90-OM are introduced into U-adsorbent for the first time. • • The maximum U-capacity of ZIF-90-OM (610 mg/g) is much higher than ZIF-90 at pH = 5. • • The removal rate of ZIF-90-OM to U (VI) is above 0.75 in the coexistence of competitive ions. • • Both ZIF-90 and ZIF-90-OM show good antimicrobial property. • • Perspectives about the adsorbent (ZIF-90-OM) of removing uranium from wastewater are presented. The anti-fouling performance of an adsorbent is important for its application in wastewater, because biological fouling severely reduces its adsorption capacity. A zeolitic imidazolate framework was synthesized and oxime-functionalized to produce an efficient uranium adsorbent with antimicrobial properties (ZIF-90-OM). Its adsorption performance for U (VI) was studied under different environmental parameters, including pH, initial uranium concentration, competitive ions, ionic strength, temperature, and contact time. Due to its porous structure and the strong chelation of oxime groups with U (VI), ZIF-90-OM showed a very high maximum adsorption capacity for U (VI) of 610 mg/g at pH = 5.0. The adsorption of uranium on ZIF-90-OM correlated well with the Langmuir model and the pseudo-second-order kinetic model. ZIF-90-OM showed high uranium selectivity even in the presence of competing metal ions. Besides, the adsorbent also exhibits good recyclability, the adsorption capacity was maintained after five adsorption/desorption cycles. Furthermore, ZIF-90-OM showed excellent antimicrobial properties against both Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus). Our work shows that ZIF-90-OM is an efficient adsorbent for the removal of U (VI) from wastewater because of the presence of oxime groups and its anti-fouling properties. Moreover, due to its antimicrobial properties, ZIF-90-OM can be used to purify water. [ABSTRACT FROM AUTHOR]

Uranium (U) is hazardous and radioactive, wastewater containing U(VI) should be treated before being discharged. Here, two novel uranium adsorbents, phosphorylated hyper-cross-linked bisphenol A (PHCP-1) and fluorene-9-bisphenol (PHCP-2) were separately synthesized via Friedel-Crafts reaction followed by phosphorylation using phosphorus oxychloride. PHCPs had a BET surface area (up to 564 m2/g) with pore sizes of 2.2–2.8 nm. These adsorbents were used for the first time for uranium adsorption from water and demonstrated outstanding adsorption performance. PHCP-2 had a great uranium adsorption capacity (297.14 mg/g) and a very fast sorption rate (85% removal rate within 5 min). The adsorption data were well fitted with Freundlich isotherm and the pseudo-second-order kinetic model. PHCPs displayed selective adsorption capacity for U(VI) from solution that including a variety of competing metal ions. The reusability was confirmed through three regeneration cycles. Based on a series of spectroscopic analyses, the mechanism of action between PHCPs and U(VI) is primarily derived from the complex between phosphate functional groups and U (VI). The sorption performance of PHCPs is attributed to their huge specific surface area and the strong complex between phosphate groups and U(VI). These findings suggest that PHCPs could be useful in the effective adsorption of uranium from water. [Display omitted] • Phosphorylation was performed on bisphenol type hyper-cross-linked polymer for the first time. • PHCPs have large BET surface area (PHCP-2 = 564 m2/g). • PHCP-2 showed a very fast sorption rate, the removal rate reached 85% within 5 min. • PHCPs showed selective adsorption ability for U(VI) from solution that contained multiple competing metal ions. [ABSTRACT FROM AUTHOR]

In this study, a mesoporous PCN-222/GO-COOH adsorbent, based on the growth of a mesoporous zirconium-metalloporphyrin metal-organic framework (PCN-222) on the carboxylated graphene oxide (GO-COOH) to recover U(VI) from wastewater, was designed and prepared through solvothermal method and ultrasonication assisted stir technique. The U(VI) adsorption performance of the PCN-222/GO-COOH adsorbent was evaluated. The results indicated that the mesoporous PCN-222/GO-COOH adsorbent could effectively recover U(VI) and show an excellent adsorption capacity (426 mg/g), which was superior to those of GO-COOH and PCN-222 probably because the complexation and synergistic effect between GO-COOH and PCN-222 were facilitated by the ultrasonication assisted stir technique. And the PCN-222/GO-COOH adsorbent showed excellent reusability and selectivity for U(VI) adsorption, which also had outstanding adsorption performances in the complex wastewater. Furthermore, the chemical and monolayer adsorption dominated the U(VI) adsorption behavior of PCN-222/GO-COOH adsorbent. The excellent adsorption capacity, selectivity and reusability for U(VI) rendered PCN-222/GO-COOH composites as a promising adsorbent for recovering U(VI) from wastewater. [Display omitted] • A mesoporous PCN-222/GO-COOH adsorbent was successfully developed. • Ultrasonication assisted stir technique facilitated the adsorbent to form complex. • The adsorbent exhibited high U(VI) adsorption capacity, Q e reached 426 mg/g. • The adsorbent showed excellent selectivity and reusability for U(VI) adsorption. • The adsorbent was employed for recovering U(VI) from wastewater environment. [ABSTRACT FROM AUTHOR]

An efficient uranium adsorbent, amidoximated polyacrylonitrile foam (AOPAN) with a hierarchical pore structure, was prepared by freezing-extraction followed by amidoximation. AOPAN was analyzed by Fourier transform infrared (FT-IR), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), and showed an excellent uranium adsorption performance in aqueous solutions; the uranium adsorption capacity was 1058 mg/g. Even in the presence of competing ions, AOPAN showed a high selective removal ability for uranium (removal rate > 85%). After three cycles, the adsorption capacity and removal rate for uranium were still higher than 800 mg/g and 90%, respectively, which indicated the good recyclability of AOPAN. Furthermore, the adsorption process fitted the Freundlich model and the pseudo-second-order kinetic model. The calculated ΔH° and ΔG° indicated that the adsorption process was endothermic. The higher adsorption temperature could promote the adsorption on AOPAN. The XPS analysis indicated that the chelation between the amidoxime group and uranium plays a key role in the adsorption of uranium on AOPAN. Unlabelled Image • Porous amidoxime modified PAN with hierarchical pore (AOPAN) prepared by freeze-extraction. • AOPAN shows high U(VI) sorption capacity of 1058 mg/g. • High selectivity and good recyclability. • Hierarchical pore and strong chelation play important role. [ABSTRACT FROM AUTHOR]