Chloramphenicol removal from water by various precursors to enhance graphene oxide-iron nanocomposites

Idham, M. F.*; Falyouna, O.*; Eljamal, R.*; Maamoun, I.; Eljamal, O.*

Journal of Water Process Engineering (Internet), 50, p.103289_1 - 103289_16, 2022/12

https://doi.org/10.1016/j.jwpe.2022.103289

Due to synthesis variation affecting various graphene oxide (GO) physicochemical parameters and cost efficiency aspects, the present study investigated the influence of GO precursor components for GO precipitated nZVI nanocomposite (nZVI/GO) and optimized removal conditions to remove chloramphenicol (CAP) from water. In order to synthesize nZVI/GO nanocomposites, four methods of GO precursor synthesis were used, denoted GO1, GO2, GO3, and GO4. A novel synthesis process is introduced based on economic and time-less-consuming protocols to produce GO precursor. A series of desorption experiments were also implemented in various eluents to clarify the CAP removal mechanism. Interestingly, this study demonstrated the substantial impact of GO precursor on the nanocomposite performance in eliminating CAP. The introduced novel GO successfully served as an excellent nZVI precipitation medium and enhanced CAP removal efficiency. Empirical optimization demonstrated that nZVI/GO4-1:1 could eliminate up to 91% of 100 mg/L CAP by dosage as low as 0.25 g/L at pH 5. nZVI/GO4 displayed CAP removal stability throughout a more comprehensive pH range, and remarkable recyclability, making it more promising and practical than bare nZVI and other analyzed nanocomposites. Kinetics data demonstrated a high degree of compatibility with the pseudo-first-order (PFO) and pseudo-second-order (PSO). Through kinetics and statistical analyses, desorption experiments, FTIR spectroscopy, and EDX analysis, nZVI/GO4 removed some of the CAP through the adsorption mechanism controlled by physisorption and chemisorption. In contrast, the oxidation mechanism eliminated the remaining CAP.

A Novel method to improve methane generation from waste sludge using iron nanoparticles coated with magnesium hydroxide

Eljamal, R.*; Maamoun, I.; Bensaida, K.*; Yilmaz, G.*; 杉原 裕司*; Eljamal, O.*

Renewable and Sustainable Energy Reviews, 158, p.112192_1 - 112192_13, 2022/04

https://doi.org/10.1016/j.rser.2022.112192

In response to the low efficiency of the anaerobic digestion (AD) process in generating methane gas, we apply for the first time the use of coated/ Fe with Mg(OH) to enhance the production rate of methane gas from the degradation of waste sludge. A series of batch tests investigated several operations factors followed by a semi-continuous operation system examined the long-term production of methane gas in the presence of the coated/ Fe were performed. The coating ratio of Mg(OH)/Fe and the dosage of coated/Fe were optimized to acquire the highest production rate of methane as 0.5% and 25 mg/gVS, respectively. Under these optimum conditions, the methane production increased by 46.6% in the batch tests and 120% in the semi-continuous operation system compared to the control reactor. The results revealed that both Fe and Mg(OH) did not significantly improve the production of methane when each one was used alone at different dosages, and the improved methane production originated from the synergetic effect of combining these two materials. The crucial role of Mg(OH) coating layer was associated with the controlled reactivity release of Fe, which was indicated by the slow release of ferrous and ferric ions in the bioreactors. Furthermore, the addition of coated/Fe stimulated bacterial growth, increased methane content, and maintained the pH within the optimum range in the bioreactors. The dosing time of coated/Fe was investigated during the four stages of AD process, and the best dosing time was found in the methanogenic stage (on Day 4). Overall, based on the experimental and predicted methane production, the coated/Fe has a great potential for the practical applications of AD.

Charge disproportionation and magnetic properties in perovskite iron oxides

葛下 かおり; 森本 正太郎*; 那須 三郎*

Physica B; Condensed Matter, 329-333(1-4), p.736 - 737, 2003/05

https://doi.org/10.1016/S0921-4526(02)02478-X

ぺロブスカイト型鉄酸化物の物理的性質はFeO八面体のネットワークに関係している。SrFeOでは起こらない電荷分離(2FeFe + Fe)が、SrのLaへの置換や次元性の変化によるFeO八面体のネットワークの切断により発現する。また、SrFeOのFeを40%Coに置換すると、磁性は反強磁性から強磁性へと変化し電荷分離も抑制される。

Dose delivered by unit amount of tritium released into the environment

村田 幹生; 野口 宏

Journal of Nuclear Science and Technology, 34(2), p.176 - 184, 1997/02

https://doi.org/10.3327/jnst.34.176

事故時を想定したトリチウムガス(HT)野外放出実験(カナダ)から、HTの単位量放出に伴う空気汚染による成人の実効線量当量(線量)を風下100mと400mで解析した。その結果、放出HTプルーム自身による線量は1%以下で、残りは環境中でHTHTO転換で2次的に生じたHTC線量であることが明らかになった。一次放出がHTOである場合を想定したとき、線量はHT放出の場合の100倍程度であることが解析から推定された。また、実測線量の、最も被ばく量が大きくなると考えられる条件への外挿、仏国で実施されたHT放出実験に基づく解析結果との比較等を含めて発表する。

閉サイクル水素製造法の研究III (1977年度)

佐藤 章一; 池添 康正; 清水 三郎; 中島 隼人; 小林 敏明

JAERI-M 7927, 43 Pages, 1978/10

JAERI-M-7927.pdf:1.33MB

核エネルギーによる閉サイクル水素製造プロセスに関する昭和52年度の研究プログレスレポートである。熱化学プロセスでは、炭酸セリウム(III)を中間反応物質とする8段反応の実行可能なプロセスを見出した。また炭酸ガスを高温で塩化鉄(II)または沃化鉄(II)と反応させて一酸化炭素を得る反応を用いて、別の実験的に可能な4段または5段の反応プロセスを見出した。さらに、硫黄サイクルの改良プロセスとして、溶媒抽出によるニッケル回収率70-80%を仮定すると、高燃焼熱基準熱効率か30-40%となる。放射線化学プロセスでは、炭酸ガスにプロパンまたは二酸化窒素を添加して、放射線照射したときの反応機構について検討した。

Se(-II) immobilization in Fe(II)-(hydro)oxides; Coprecipitation and post-transformation behavior

Francisco, P. C. M.; 石寺 孝充; 舘 幸男

no journal, , 

As a key long-lived fission product in high-level wastes (HLW), Se-79 presents a significant contribution to the long-term radiological hazards associated with geological HLW disposal. Thus, its behavior is important for the performance assessment of geological HLW repositories. Under reducing conditions Se exists as Se(-II). A possible retardation pathway for Se(-II) species is via interaction with aqueous Fe(II) from the corrosion of the steel canister enclosing the waste matrix. There is relatively little information on Se(-II) uptake involving coprecipitation with poorly crystalline iron phases and subsequent behavior during phase transformation. Batch coprecipitation and crystallization experiments of Se(-II) with Fe(II) phases under N atmosphere and reducing conditions were carried out. Rapid Se(-II) uptake was observed during coprecipitation. During aging, Se(-II) was observed both as discrete phases and surface complexes.

Development of a sensor for in-situ measurement of hydrogen peroxide in irradiation field by using frequency dependent complex impedance analysis

塙 悟史; 端 邦樹; 内田 俊介; 西山 裕孝

no journal, , 

原子力プラントの冷却水は原子炉内部で放射線を受け分解し、水中には過酸化水素などの酸化剤が生成される。過酸化水素は、応力腐食割れ(SCC)の発生やき裂進展などプラントの経年劣化現象の主要因子であり、その場の濃度の定量評価は高経年化プラントの健全性を評価する上で重要である。しかし、過酸化水素濃度の定量評価は、従来の技術ではサンプリング水の分析による必要があり、熱的に不安定な過酸化水素のその場評価は難しい。周波数依存複素インピーダンス(FDCI)測定によれば、材料表面の酸化皮膜の性状変化を把握することが可能であり、Cole-Coleプロットの低周波数側半円が過酸化水素濃度に対してリニアな相関を示すことが最近の研究で明らかになっている。原子力機構では、FDCI測定を応用した照 射環境下でも使用できる過酸化水素濃度のその場測定センサーの開発を進めている。本発表では、上記センサーの開発計画を紹介する。