Shahr El-Din Ahmed M, Abdelbary Hanan M, Hamed Mostafa M, Hilal Moustafa A, Borai Emad H, Elafifi Elsayed M
Analytical Chemistry and Control Department, Hot Laboratories and Waste Management Center (HLWMC), Egyptian Atomic Energy Authority (EAEA), 13759, Cairo, Egypt.
Analytical Chemistry and Control Department, Hot Laboratories and Waste Management Center (HLWMC), Egyptian Atomic Energy Authority (EAEA), 13759, Cairo, Egypt.
J Environ Radioact. 2025 Nov;290:107794. doi: 10.1016/j.jenvrad.2025.107794. Epub 2025 Sep 5.
The huge volume waste of the produced water (PW) associated with petroleum extraction poses significant hazards to the surrounded environment due to its complex composition and the presence of various hazardous pollutants, including organic, inorganic, biological contaminants, and natural occurring radioactive materials (NORM). This study was conducted to investigate the factors affecting the removal of the long-lived radium isotopes, i.e., Ra (1600 y) and Ra (5.8 y), from PW associated with oil and natural gas production in certain Egyptian oilfield. The total radium concentration (Ra + Ra) in PW was found to be 164 Bq/L, i.e., 3.145 ng/L. Isotherm, thermodynamic, kinetic and adsorption mechanism were carried out for the removal of Ra-isotopes in PW using powdered activated carbon (PAC) as adsorbent material. The removal efficiency of Ra-isotopes was found to be affected by pH, adsorbent dosage, temperature, and contact time. The maximum removal efficiency exceeded 97 ± 3 % under optimal conditions (pH∼5, 23 ± 2 °C and 3 h contact time). Moreover, it was revealed that the adsorption mechanism of Ra isotopes removal in PW is heterogeneous process controlled by both Freundlich (R = 0.998) and Dubinin-Radushkevich (R = 0.970) isotherms. The process followed the pseudo-second-model (R = 0.998), and was endothermic up to temperatures below 40 °C. At the optimal conditions, the maximum adsorption capacity (q) of Ra from PW onto PAC reached 0.77 ng/g (40 Bq/g) after 3 h at pH 5 ± 0.02 and 23± 2 °C. At these conditions, removal of Ra-isotopes from PW using PAC could be mainly due to surface complexation mechanism. As a result, the activity concentration (Bq/L) and natural radiation dose rate (μ Sv/h) of total radium (Ra + Ra) in PW were reduced below the exemption limits (<10 Bq/L, <0.1 μ Sv/h) recommended internationally. Furthermore, the data is efficient and promising for designing a prototype for NORM removal from PW generated in petroleum industry prior to its discharge into the surrounded environment.
与石油开采相关的采出水（PW）产生的大量废弃物，因其复杂的成分以及各种有害污染物（包括有机、无机、生物污染物和天然存在的放射性物质（NORM））的存在，对周边环境构成了重大危害。本研究旨在调查影响从埃及某油田与石油和天然气生产相关的采出水中去除长寿命镭同位素（即镭 - 226（半衰期1600年）和镭 - 228（半衰期5.8年））的因素。采出水中总镭浓度（镭 - 226 + 镭 - 228）被发现为164 Bq/L，即3.145 ng/L。使用粉末活性炭（PAC）作为吸附材料，对采出水中镭同位素的去除进行了等温线、热力学、动力学和吸附机理研究。发现镭同位素的去除效率受pH值、吸附剂用量、温度和接触时间的影响。在最佳条件（pH值约为5、23 ± 2°C和3小时接触时间）下，最大去除效率超过97 ± 3%。此外，研究表明采出水中镭同位素去除的吸附机理是由弗伦德里希等温线（R = 0.998）和杜比宁 - 拉杜舍维奇等温线（R = 0.970）控制的非均相过程。该过程遵循准二级模型（R = 0.998），并且在温度低于40°C时是吸热的。在最佳条件下，在pH值5 ± 0.02和23 ± 2°C下3小时后，采出水中镭在PAC上的最大吸附容量（q）达到0.77 ng/g（40 Bq/g）。在这些条件下，使用PAC从采出水中去除镭同位素可能主要归因于表面络合机理。结果，采出水中总镭（镭 - 226 + 镭 - 228）的活度浓度（Bq/L）和天然辐射剂量率（μSv/h）降低到国际推荐的豁免限值以下（<10 Bq/L，<0.1 μSv/h）。此外，这些数据对于设计一个在石油工业产生的采出水排放到周边环境之前去除NORM的原型是有效且有前景的。
