JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY
·
2019
·Vol. 323
·期 2
·993-1002
·
IF 1.186
Ma Zhili,Wang Yanfei,Luo Yige,Xie Xiaoqing,Xiong Zeng
Highly crosslinked organic–inorganic hybrid polymer poly(cyclotriphosphazene-co-melamine) microspheres (PZM) were synthesized by a simple method. The microspheres was characterized by FTIR, SEM and EDX. It was applied to eliminate thorium(IV) from aqueous solution under various conditions, i.e., pH, initial concentration, dosage and contact time. The experimental data were well-imitated via the pseudo-second-order kinetic model and its adsorption processes comply with the Langmuir isotherm model. Adsorption thermodynamic studies demonstrated that the adsorption process, in essence, was spontaneous and endothermic. Furthermore, the maximum experimental adsorption capacity was 98.6 mg g −1 for initial thorium(IV) concentration 50 mg L −1 . When pH = 0.0, the thorium(IV) removal efficiency reached at 76.9%, which indicates that the adsorbent can also was used in a peracid environment. Adsorption behavior of thorium(IV) onto the microspheres were weakly affected via temperature, implying that adsorption would be done at room temperature.
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JOURNAL OF VINYL & ADDITIVE TECHNOLOGY
·
2023
·
IF 2.7
Maoyong Zhi,Yinlong Zhao,Xiong Yang,Shansong Gao,Bingjian Su,Quanyi Liu
Epoxy resin is widely applied in civil aircraft, automobile and electronics products because of its good processing, adhesion, and mechanical properties, but its application is limited due to its easy combustion. Therefore, it is worthwhile to carry out flame-retardant treatment for epoxy resin. In this study, a new bio-based three-source integrated intumescent flame-retardant cyclodextrin phosphate melamine salt (CDPM) was synthesized from β-cyclodextrin, phosphoric acid, and melamine, and it was employed as an additive flame retardant to fabricate CDPM/epoxy resin (CDPM/EP) composites. Thermogravimetric analysis results manifested that CDPM slightly improved the thermal stability of CDPM/EP composites. The CDPM/EP composite containing 10 wt.% CDPM acquired a limiting oxygen index of 32.9% and passed UL94 V-0 rating. Moreover, the peak heat release rate, total heat release, and total smoke production, were respectively decreased by 46.4%, 55.5%, and 61.8% in contrast with neat epoxy resin. These results demonstrated that CDPM/EP could exert excellent flame retardance and smoke suppression performance. Scanning electron microscope and Raman results confirmed that CDPM facilitated the formation of residual char. Moreover, thermogravimetric/infrared results showed that CDPM/EP produced plenty of phosphorus-containing free radicals and nonflammable NH 3 during pyrolysis process, which played a good flame retardance effect in gas phase. This study provides a new approach for the design and development of low-cost intumescent bio-based flame retardant for epoxy resin. Highlights Novel three-source intumescent bio-based flame-retardant CDPM was successfully synthesized. CDPM was incorporated into epoxy resin as an additive flame retardant. Only 10 wt.% CDPM provided 55.5% and 61.8% reductions of total heat release and total smoke production, respectively. CDPM/EP composites exhibited an excellent flame retardancy and smoke suppression properties. The outstanding promoting carbonization effect of CDPM in condensed phase contributes to reduce the release of heat and smoke.
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ChemistrySelect
·
2023
·Vol. 8
·期 34
·e202301801
·
IF 2.1
Xuedong Fu,Ruijie Li,Shengguo Yan,Weiyong Yuan,Yonggang Zhang,Wei Sun,Xuefei Wang
Graphical Nitrogen-doped porous carbons were prepared by pyrolysis of polyacrylonitrile films doped with melamine or graphitic carbon nitride obtained by thermal condensation of melamine. Compared with melamine, g-C 3 N 4 was more efficient in nitrogen doping and porous structure, which mainly resulted from the high thermostability and large size of the dopant, thus enhancing the supercapacitor performance. Melamine and graphitic carbon nitride (g-C 3 N 4 ) obtained by thermal condensation of melamine were doped in polyacrylonitrile (PAN) films. Nitrogen-doped porous carbons were then prepared by pyrolysis of the composite films. Though all the porous carbons had a high nitrogen content of at least 10 %, g-C 3 N 4 was more efficient than melamine in nitrogen doping. The nitrogen content was elevated with the increase of the amount of each dopant, the highest value of 19.0 % was achieved by g-3 (porous carbon obtained from the PAN/g-C 3 N 4 composite film with a mass ratio of 3). Amongst the nitrogen functionalities, pyridinic-N and pyrrolic-N held a percentage of at least 80 %. Compared with the carbon materials obtained from melamine doped PAN films, those from g-C 3 N 4 doped ones exhibited larger surface area and average pore size, and higher pore volume. The difference mainly resulted from the thermostability and size of the dopants. The g-C 3 N 4 doped materials thus presented more excellent electrochemical properties. The specific capacitance of g-3 electrode was 135.3 F/g at a current density of 0.5 A/g. Rather than melamine, g-C 3 N 4 could improve the chemical composition and textural properties of the carbon materials, thus enhancing their supercapacitor performance.
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Journal of Water Process Engineering
·
2023
·
IF 7
Junna Yan,Mengyu Ma,Bo Zhao,Feihu Li
Excessive discharge of phosphorus (P) to natural watercourses not only causes eutrophication of water bodies but also results in the loss of P resources. P-containing wastewater is a crucial secondary P resource. Zirconium-based metal-organic frameworks (MOFs), particularly UiO-66 has been shown great promise in efficiently capturing P from water. In this study, a group of UiO-66@sponge composites was prepared by a facile layer-by-layer in-situ growth approach using melamine sponge (MS) as scaffolds. The as-prepared UiO-66@sponge composites exhibit high chemical and dimensional stability when used as adsorbents for reclaiming P from wastewater. Batch adsorption results show that one UiO-66@sponge composite exhibited the highest phosphorus adsorption capacity of 83.55 mg g −1 at pH 6.0, outperforming most other UiO-66 adsorbents under environmentally relevant conditions. The intrinsic mechanical flexibility and chemical stability of these UiO-66@sponge composites enable us to efficiently enrich phosphorus from a dilute solution by a rapid adsorption-desorption operation. This work provides a promising strategy to integrate MOFs with dimensionally stable and flexible sponges for rapid adsorption and recovery of phosphate from wastewater and could be potentially expanded to the recovery of other value-added or technology-critical elements from waste streams.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2023
·
IF 5.2
Keliang Song,Zhipeng Liu,Aoshuang Yang,Yongsheng Li,Fangfang He,Zhuoni Jiang,Xiaoan Li,Zhengguo Chen,Wenbin Yang
Hydrated salt phase change materials (PCMs) have the advantages of high energy storage density and low cost, and have great application prospects in the field of phase change energy storage. However, the problems of supercooling, phase separation and leakage of hydrated salt PCMs limit their further applications. In this work, we designed and fabricated Cu-coated melamine foam (MF)/barium hydroxide octahydrate (BHO) shape-stabilized phase change materials (SSPCMs) with low supercooling. MF was used as supporting material and Cu as a nucleating agent and thermal conductivity enhancer by loading it onto MF via electroless plating . BHO was then encapsulated into the MF@Cu skeleton through vacuum impregnation to obtain BHO@MF@Cu SSPCMs. The results demonstrated that BHO@MF@Cu SSPCMs not only present very low supercooling degree of 0.12 °C and high thermal energy capacity of 247 J/g, but maintained a latent heat of phase transition of 229.3 J/g with little change in enthalpy after 100 thermal cycles. Moreover, compared to BHO, SSPCMs exhibited high thermal conductivity of 1.687 W m −1 K −1 , excellent shape stability, and thermal cycling stability. In summary, BHO@MF@Cu SSPCMs with low supercooling degree were prepared by electroless plating and vacuum impregnation in this study, which provides a new strategy to reduce the supercooling degree of hydrated salt PCMs.
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FOOD CHEMISTRY
·
2023
·
IF 8.8
Yichang He,Yiquan Liao,Bin Zhang,Ruiqi Xu,Ye Ma,Minggang Zhao,Hongzhi Cui
Melamine added to milk powder can lead to kidney injury and even death, but rapid detection is still hard due to the strong interference of milk powder solution. Herein, the CC/CeO 2 /CNPs mesh was constructed to detect melamine by using the photo-enhanced barrier effects on electrochemical response. Schottky barrier was regulated effectively to produce electrochemical response to melamine by photo-induced electrostatic interaction, which exhibited strong resistance to interference in milk powder solution. Sensitivity was enhanced by nearly 5 times and the lowest detection limit was reduced as low as 0.274 nM. The obtained high recovery (100%-104%) and good stability in milk powder solution indicated the good potential for practical applications. It provides a new opportunity for achieving strong resistance to interference by using the photo-enhanced barrier driving effect on electrochemical response.
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PubMed
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ACS Applied Nano Materials
·
2023
·
IF 5.9
Fan Wu,Xiangxiao Meng,Zongxing Liu,Tiantian Lv,Long Yu,Jiarong Zhang,Ya’nan Zhao,Chang Zhao,Guangjian Xing
Flexible and long-term stable piezoresistive sensors still have room for improvement, in terms of sensitivity and cost reduction. Therefore, future research will focus on developing pressure-sensitive materials with improved performance and reduced cost. This study presents a stable suspension of Ta4C3 nanosheet using an etching and intercalation method. Subsequently, a Ta4C3 nanosheet/melamine sponge was created through a dipping-drying method and utilized as a flexible framework for wearable piezoresistive sensors. The sensors demonstrate exceptional pressure-sensing performance, including a high sensitivity (4.01 kPa–1) over a wide linear range of 0.018–12.06 kPa, a low hysteresis, a low detection limit (18.5 Pa), a short response time (35.4 ms), and a quick recovery time (27.88 ms), as well as long-term stability and durability. These sensors can be utilized for real-time monitoring of various physiological activities in the human body. Moreover, they hold potential applications in wirelessly detecting human movement and robot motion.
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Progress in Natural Science-Materials International
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2023
·
IF 4.7
Jiahao He,Wenlu Zhang,Xinpeng Jin,Chong He,Wenbin Li
To achieve the scalable production of high-performance melamine-based flame retardant nanofibers , solution blowing spinning technology was employed into the continuous spinning of melamine(MA)@polyacrylonitrile(PAN) composite fibers. Propelled by the compressed air current, spinnable MA@PAN solutions can be shaped into nanofiber with a high flow rate over 50 mL/h. Among different melamine-based materials, melamine phosphate (MPP) exhibited excellent solubility in the solution, exceeding 30 wt%, ensuring that the MPP@PAN nanofiber products demonstrated exceptionally robust flame-retardant performance. Furthermore, through fiber textile needle punching technology, loose fiber sponge can be organized into enhanced fiber blankets. These MPP@PAN nanofiber products exhibited outstanding flame retardant and thermal insulation properties, rendering them pivotal as the flame-retardant materials in extreme environments.
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MICROPOROUS AND MESOPOROUS MATERIALS
·
2023
·
IF 5.2
Song Yan,Cao Chaochao,Shaobo Yang,Jiawei Ji,Zheng Zhou,Yaxin Gu,Chaoze Liu,Rongjuan Zhang,Yanming Xue,Chengchun Tang
Development of porous micro-nanomaterials with excellent physical and chemical stability as adsorbents for effective water cleanup still has huge practical implications. Here, hierarchically porous boron nitride nanosheets (BNNSs) with abundant active groups (-OH and –NH 2 ) and defective structures were prepared via the incorporation of phosphoric acid into melamine borate (M·2B) to form a melamine phosphate and borate assembly and subsequent pyrolysis . Phosphoric acid can interact with melamine through hydrogen bonding , which not only changes the micromorphology of porous BN materials but also regulates their chemical compositions and bonding states. The resulting porous BNNSs show a specific surface area as high as 1477.923 m 2 /g and a large pore volume . Encouraged by these characteristics, the resulting porous BNNSs exhibit remarkable adsorption capabilities for methylene blue (MB) in alkaline solution up to 750 mg/g and oxytetracycline (OTC) in acidic solution up to 128 mg/g. Additionally, they have excellent cyclic adsorption performance, suggesting a high practical value in wastewater purification. Therefore, this work not only presents the practical application of porous BNNSs in sewage treatment but also provides a designing scheme for preparing variety micro- and nano-BN materials by regulating and controlling the transformation of melamine salts.
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AICHE JOURNAL
·
2023
·Vol. 69
·期 11
·e18192
·
IF 3.7
Guanglu Xia,Jianhao Qiu,Dingliang Dai,Lu Zhang,Yong Tang,Jianfeng Yao
A series of covalent organic frameworks (COFs) with β-ketoenamine linkages named TpTt-COF, TAPT-COF, and TpPa-1 were constructed for photocatalytic H 2 O 2 generation in pure water and ambient air under visible light. Among them, TpTt-COF performed striking H 2 O 2 yield of 2647 μmol L −1 , which is 3.5, 17.5, and 176.5-fold those of TAPT-COF, TpPa-1, and bulk g-C 3 N 4 , respectively, attributing to the electron-deficient trait, short charge diffusion distance, and the narrowest bandgap of TpTt-COF. Additionally, to achieve the facile recovery, TpTt-COF was firmly and evenly anchored on melamine sponges (MS) because plenty of amino groups on the surface of MS could be involved in the β-ketoenamine formation and guide the synthesis of TpTt-COF on MS. The corresponding H 2 O 2 evolution over this photocatalyst monolith is also respectable and can be well repeated at least four times. This work is quite instructive for photocatalyst construction based on covalent organic frameworks and facile photocatalytic applications.
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MATERIALS CHEMISTRY AND PHYSICS
·
2023
·
IF 4.6
Xiaolu Zhang,Qianqian Zhang,Hui Su,Yafei Xu,Ling Li
A superhydrophobic and superoleophilic sponge (MS/UIO-66(F 4 )/RGO/PDMS) was fabricated by decorating the skeleton of a melamine sponge (MS) with UIO-66(F 4 ) nanoparticles and reduced graphene oxide (RGO) nanosheets layer by layer, and then hydrophobic modification with polydimethylsiloxane (PDMS). The composition, morphology, thermal stability, and wettability of the modified sponge were characterized, and its oil/water separation application was investigated. Characterization results reveal that compared with the hydrophilic pure MS, the fiber surface of the prepared sponge becomes rough and demonstrates remarkable super-hydrophobicity with a water contact angle of 153.5°. The modified sponge can efficiently separate water-in-diesel emulsion (flux of 3665 L · m −2 · h −1 ) and multiple stratified oil-water mixtures via the auxiliary device with a separation efficiency above 98.3%, which has no significant change after 25 cycles. The modified sponge can absorb oils or organic solvents 48–100 times higher than its weight, with a stable absorption capacity after 20 cycles. Moreover, it can be applied in handling flammable oils, showing good flame retardancy. Considering it also possesses excellent chemical stability, extreme environmental stability (resistance to high/low temperature, UV irradiation and load-bearing) and mechanical durability under harsh conditions, the modified sponge is a promising candidate in the field of oily wastewater treatment.
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JOURNAL OF FIRE SCIENCES
·
2023
·
IF 1.9
Chenran Fan,Lijuan Wei,Shicheng Zhao
To improve the flame retardant efficiency of intumescent flame retardants, some nano-scale additives as synergists were always added. In this work, nano silicon and piperazine pyrophosphate/melamine polyphosphate into polypropylene was investigated, which was obviously efficient to improve thermal stability and flame retardancy. The optimal synergistic ratio corresponded to 1 wt% SiO2, 10 wt% piperazine pyrophosphate, and 5 wt% melamine polyphosphate. The system passed the UL-94 V-1 classification and had a limiting oxygen index value of 34.5%. It exhibited a decrease on peak heat release rate and peak smoke production rate by 81% and 80%, respectively. Based on characterizations of scanning electron microscope, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy, the synergistic mechanism was investigated. A reactive cross-linking network between SiO2 and piperazine pyrophosphate/melamine polyphosphate during burning was formed to enhance the structure of carbon protective layer. Nano silicon acted as a foaming nucleating agent to promote the formation of porous dense carbon layer in intumescent flame retardants during burning. The synergistic strategy of SiO2 and piperazine pyrophosphate/melamine polyphosphate provided new compounded system for the design of polymeric materials with excellent flame retardancy, great thermal stability, and low release of heat and smoke.
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