Structure and phase analysis of one-pot hydrothermally synthesized FePO4-SBA-15 as an extremely stable catalyst for harsh oxy-bromination of methane

Wang, Runqin; Lin, Rui‐Biao; Ding, Yunjie; Liu, Jia; Wang, Junhu; Zhang, Tao

doi:10.1016/j.apcata.2012.12.022

Cited by 14 publications

(18 citation statements)

References 31 publications

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“…Under the high DO levels (7e9 mg/L) applied in reactors in this study, part of Fe 2þ could be inevitably and easily oxidized to Fe 3þ and then form the stable crystal of iron phosphate (Fe 7 (PO 4 ) 6 ). Moreover, FePO 4 crystal can be gradually transformed into iron phosphate (Fe 7 (PO 4 ) 6 ) by redox reactions (Gadgil and Kulshreshtha, 1994;Wang et al, 2013) created in the granules. Therefore, it could be confirmed that w a t e r r e s e a r c h 6 8 ( 2 0 1 5 ) 4 2 3 e4 3 1 hydroxyapatite (HAP) and iron phosphate (Fe 7 (PO 4 ) 6 ) were the major inorganic P in the nitrifying aerobic granules in this study.…”

Section: 4mentioning

confidence: 99%

Identification of inorganic and organic species of phosphorus and its bio-availability in nitrifying aerobic granular sludge

et al. 2015

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Phosphorus (P) recovery from sewage sludge is necessary for a sustainable development of the environment and thus the society due to gradual depletion of non-renewable P resources. Aerobic granular sludge is a promising biotechnology for wastewater treatment, which could achieve P-rich granules during simultaneous nitrification and denitrification processes. This study aimed to disclose the changes in inorganic and organic P species and their correlation with P mobility and bio-availability in aerobic granules. Two identical square reactors were used to cultivate aerobic granules, which were operated for 120 days with influent ammonia nitrogen (NH₄-N) of 100 mg/L before day 60 and then increased to 200 mg/L during the subsequent 60 days (chemical oxygen demand (COD) was kept constant at 600 mg/L). The aerobic granules exhibited excellent COD removal and nitrification efficiency. Results showed that inorganic P (IP) was about 61.4-67.7% of total P (TP) and non-apatite inorganic P (NAIP) occupied 61.9-70.2% of IP in the granules. The enrichment amount of NAIP and apatite P (AP) in the granules had strongly positive relationship with the contents of metal ions, i.e. Fe and Ca, respectively accumulated in the granules. X-ray diffraction (XRD) analysis and solution index calculation demonstrated that hydroxyapatite (Ca₅(PO₄)₃(OH)) and iron phosphate (Fe₇(PO₄)₆) were the major P minerals in the granules. Organic P (OP) content maintained around 7.5 mg per gram of biomass in the aerobic granules during the 120 days' operation. Monoester phosphate (21.8% of TP in extract), diester phosphate (1.8%) and phosphonate (0.1%) were identified as OP species by Phosphorus-31 nuclear magnetic resonance (³¹P NMR). The proportion of NAIP + OP to TP was about 80% in the granules, implying high potentially mobile and bio-available P was stored in the nitrifying aerobic granules. The present results provide a new insight into the characteristics of P species in aerobic granules, which could be helpful for developing P removal and recovery techniques through biological wastewater treatment.

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Section: 4mentioning

confidence: 99%

Identification of inorganic and organic species of phosphorus and its bio-availability in nitrifying aerobic granular sludge

et al. 2015

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“…Since 2005, owing to the strong incentive of the discovery of large reserves of unconventional natural gas and the advances achieved in hydrogen halide recovery by catalytic oxidation, a renewed interest was witnessed in methane oxyhalogenation using both HCl and HBr as the halogenating agents over a wide range of catalysts such as precious metals, 58,60,290,291 metal oxides/oxychlorides, 188,194,264,292 and metal phosphate catalysts. 61,[293][294][295][296] The following discussions are split into two parts i.e. oxychlorination and oxybromination, as the chemistry involved between them is believed to be different.…”

Section: Methane Oxyhalogenationmentioning

confidence: 99%

“…iron phosphates with the aim of achieving equimolar CH3Br plus CO (a presumed feedstock for acetic acid synthesis). 291,[293][294][295][296] A 10 wt.% FePO4/SiO2 catalyst prepared by impregnation led to a methane conversion of 50% and a total selectivity of 96% for CH3Br and CO (CH3Br:CO ~1) at 843 K. 296 The catalyst showed a relatively stable performance for 100 h on stream, but severe reduction in catalyst surface area (from 363 to 36 m 2 g −1 ) and coke deposition were observed. 294 This was claimed to be resulted from the accumulation of CH2Br2 which was identified as the predominant precursor of deposited coke in the CH3Br-to-olefins transformation.…”

Section: Iron Phosphates Ding Et Al Studied Methane Oxybromination Over a Series Of Bulk And Supportedmentioning

confidence: 99%

Halogen-Mediated Conversion of Hydrocarbons to Commodities

2017

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Halogen chemistry plays a central role in the industrial manufacture of various important chemicals, pharmaceuticals, and polymers. It involves the reaction of halogens or halides with hydrocarbons, leading to intermediate compounds which are readily converted to valuable commodities. These transformations, predominantly mediated by heterogeneous catalysts, have long been successfully applied in the production of polymers. Recent discoveries of abundant conventional and unconventional natural gas reserves have revitalized strong interest in these processes as the most cost-effective gas-to-liquid technologies. This review provides an in-depth analysis of the fundamental understanding and applied relevance of halogen chemistry in polymer industries (polyvinyl chloride, polyurethanes, and polycarbonates) and in the activation of light hydrocarbons. The reactions of particular interest include halogenation and oxyhalogenation of alkanes and alkenes, dehydrogenation of alkanes, conversion of alkyl halides, and oxidation of hydrogen halides, with emphasis on the catalyst, reactor, and process design. Perspectives on the challenges and directions for future development in this exciting field are provided.

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“…At similar performance, hydrothermally synthesized FePO 4 -SBA-15 was stable for even 1,000 h time on stream [103]. Recently, Ding et al [104] studied the very rich solid state chemistry on bulk model iron phosphate catalysts using XRD, Mössbauer spectroscopy and temperature programmed reduction.…”

Section: Methane Halogenation and Oxy-halogenationmentioning

confidence: 99%

Methane Activation by Heterogeneous Catalysis

2014

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Methane activation by heterogeneous catalysis will play a key role to secure the supply of energy, chemicals and fuels in the future. Methane is the main constituent of natural gas and biogas and it is also found in crystalline hydrates at the continental slopes of many oceans and in permafrost areas. In view of this vast reserves and resources, the use of methane as chemical feedstock has to be intensified. The present review presents recent results and developments in heterogeneous catalytic methane conversion to synthesis gas, hydrogen cyanide, ethylene, methanol, formaldehyde, methyl chloride, methyl bromide and aromatics. After presenting recent estimates of methane reserves and resources the physico-chemical challenges of methane activation are discussed. Subsequent to this recent results in methane conversion to synthesis gas by steam reforming, dry reforming, autothermal reforming and catalytic partial oxidation are presented. The high temperature methane conversion to hydrogen cyanide via the BMA-process and the Andrussow-process is considered as well. The second part of this review focuses on one-step conversion of methane into chemicals. This includes the oxidative coupling of methane to ethylene mediated by oxygen and sulfur, the direct oxidation of methane to formaldehyde and methanol, the halogenation and oxyhalogenation of methane to methyl chloride and methyl bromide and finally the non-oxidative methane aromatization to benzene and related aromates. Opportunities and limits of the various activation strategies are discussed.

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Structure and phase analysis of one-pot hydrothermally synthesized FePO4-SBA-15 as an extremely stable catalyst for harsh oxy-bromination of methane

Cited by 14 publications

References 31 publications

Identification of inorganic and organic species of phosphorus and its bio-availability in nitrifying aerobic granular sludge

Identification of inorganic and organic species of phosphorus and its bio-availability in nitrifying aerobic granular sludge

Halogen-Mediated Conversion of Hydrocarbons to Commodities

Methane Activation by Heterogeneous Catalysis

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