Structural evolution drives functional activation of oil shale semicoke as natural organic/inorganic nanocomposites

Abstract

Oil shale semicoke (OSSC) is a naturally occurring organic/inorganic nanocomposite with potential for sustainable functional applications, yet its high-value utilization is limited by an insufficient understanding of component occurrence and structural evolution. Herein, hydrothermal-assisted nitric acid treatment was employed to regulate the full-component evolution of OSSC by coupling acid etching with oxidative reconstruction. Various characterizations revealed that pristine OSSC consisted mainly of organic matter, quartz, kaolinite, magnetite, and amorphous components, in which mineral phases were closely covered or encapsulated by organics, and trace heteroatoms contributed to lattice defects. Under low nitric acid concentration, partial dissolution of metal ions and oxidation of organic matter generated a more developed pore structure, oxidized functional groups, and amorphous ferric sulfate, while the kaolinite framework was partially preserved due to organic-mediated protection. At higher concentration of nitric acid, extensive oxidation decomposed most organics and promoted the transformation of ferric sulfate species into ordered jarosite crystals. However, acid treatment alone caused secondary passivation of active sites by metal–organic complexation and positively charged mineral species. Subsequent alkali impregnation released these blocked sites and markedly enhanced adsorption activity. The optimized OSSC exhibited removal ratios of 97% for methylene blue and 54% for tetracycline, far exceeding those of raw OSSC. This work clarifies the occurrence–evolution–function relationship of OSSC and provides a mechanistic basis for converting mineral-rich solid waste into functional materials.

Keywords

Oil shale semicoke / Mineral-rich solid waste / Structural evolution / Functional activation / Structure–activity relationship

References

[1] J.P. Jahnke, D. Kim, D.J. Wildemuth, J. Nolla, M.W. Berkow, H. Gwak, S. Neyshtadt, T. Segal-Peretz, G.L. Frey, B.F. Chmelka, Mesostructured materials with controllable long-range orientational ordering and anisotropic properties, Adv. Mater. 35 (51) (2023) 230-6800.

[2] Y. Hou, M.M. Jin, D. Sun, J.F. Li, R.Y. Bi, L. Zhang, S.S. Zhu, Multifunctional inorganic/organic nanocomposite microspheres-reinventing eggs for bone repair applications, Compos. Part. B Eng. 255 (2023) 110-644.

[3] J.Q. Xu, J.W. Bartels, D.A. Bohnsack, T.C. Tseng, M.E. MacKay, K.L. Wooley, Hierarchical inorganic-organic nanocomposites possessing amphiphilic and morphological complexities: influence of nanofiller dispersion on mechanical performance, Adv. Funct. Mater. 18 (18) (2008) 2733-2744.

[4] B.C. Luo, Z.H. Shen, Z.M. Cai, E.K. Tian, Y. Yao, B.W. Li, A. Kursumovic, J.L. MacManus-Driscoll, L.T. Li, L.Q. Chen, X.H. Wang, Layered nanosheets: superhierarchical inorganic/organic nanocomposites exhibiting simultaneous ultrahigh dielectric energy density and high efficiency, Adv. Funct. Mater. 31 (8) (2021) 2170050.

[5] L. Xiang, L.Q. Sheng, C.Q. Wang, L.X. Zhang, Y.C. Pan, Y.S. Li, Amino-functionalized ZIF-7 nanocrystals: Improved intrinsic separation ability and interfacial compatibility in mixed-matrix membranes for CO₂/CH₄ separation , Adv. Mater. 29 (32) (2017) 1606999.

[6] Y.R. Sun, B. Yu, Y. Liu, J.B. Yan, Z.X. Xu, B. Cheng, F.L. Huang, J. Wang, Bio-inspired surface manipulation of halloysite nanotubes for high-performance flame retardant polylactic acid nanocomposites, Nano Res. 17 (3) (2024) 1595-1606.

[7] H. Kwak, J.S. Kim, D. Han, J.S. Kim, J. Park, G. Kwon, S.M. Bak, U. Heo, C. Park, H.W. Lee, K.W. Nam, D.H. Seo, Y.S. Jung, Boosting the interfacial superionic conduction of halide solid electrolytes for all-solid-state batteries, Nat. Commun. 14 (2023) 2459.

[8] F. Zhao, B. Mu, T.H. Zhang, C.J. Dong, Y.F. Zhu, L. Zong, A.Q. Wang, Synthesis of biochar/clay mineral nanocomposites using oil shale semi-coke waste for removal of organic pollutants, Biochar 5 (1) (2023) 7.

[9] Y.B. Xu, P.C. Sun, S.Q. Yao, Z.J. Liu, X.M. Tian, F. Li, J.Q. Zhang, Progress in exploration, development and utilization of oil shale in China, Oil Shale 36 (2) (2019) 285-304.

[10] Q.C. Yang, X.F. Li, Y. Qian, D.W. Zhang, Technical and economic analysis of an oil shale comprehensive utilization process with solid heat carrier technology, Carbon Resour. Convers. 1 (3) (2018) 266-272.

[11] J.C. Wang, Research on resource utilization of oil shale semi-coke, China Resour. Compr. Util. 40 (80) (2022) 95-98.

[12] F. Zhao, B. Mu, Y.R. Kang, D.D. Wang, G. Zhu, A.Q. Wang, Hydrothermal-assisted acid-etching of oil shale semi-coke for preparation of mineral/biochar nanocomposites and selective adsorption toward mycotoxins, J. Environ. Chem. Eng. 12 (4) (2024) 113259.

[13] X.C. Li, J.W. Shang, X.R. Gan, S.H. Cao, T.N. Zhang, J. Nie, D. Feng, X.W. Cheng, Recent advances in environmental applications of semi-coke: energy storage, adsorption and catalysis, J. Environ. Chem. Eng. 12 (2) (2024) 112430.

[14] S.W. Fan, J.W. Shang, S. Kulan, X.Y. He, X.L. Wang, B.T. Nasen, J. Nie, D. Feng, X.W. Cheng, Enhanced degradation of carbamazepine in water over SC-modified NiFe₂S₄ nanocomposites by peroxymonosulfate activation , Chem. Eng. J. 450 (2022) 138190.

[15] D.D. Wang, B. Mu, F. Zhao, L. Zong, A.Q. Wang, Fabrication of mesoporous biochar/silicate nanocomposites via full-component sustainable utilization of oil shale semi-coke waste for efficient removal of pollutants, Mater. Today Sustain. 25 (2024) 100687.

[16] R.D. Duan, Y.J. Feng, J.L. Gu, M.H. Wang, B.N. He, L.L. Liu, B.J. Zhu, X.D. Wang, Ultralow loading of Cu₂O/CuO nanoparticles on metal-organic framework-derived carbon octahedra and activated semi-coke for highly efficient SO₂ removal , J. Clean. Prod. 341 (2022) 130823.

[17] Y. Wang, X.P. Li, Z. Huang, H.Z. Wang, Z.L. Chen, J.F. Zhang, X.R. Zheng, Y.D. Deng, W.B. Hu, Amorphous Mo-doped NiS_0.5Se_0.5 nanosheets@crystalline NiS_0.5Se_0.5 nanorods for high current-density electrocatalytic water splitting in neutral media , Angew. Chem. Int. Ed. 62 (6) (2023) e202215256.

[18] B.T. Kaya, R. Bozbay, N. Orakdogen, Mechanistic insights for (alkyl)methacrylate-based cationic hybrid gels reinforced with sepiolite, montmorillonite, mica, bentonite and kaolin: A comparative thermodynamic study with all-in-one formulations, Appl. Clay Sci. 279 (2026) 108016.

[19] G.T. Zhou, Y.L. Wang, T.G. Qi, Q.S. Zhou, G.H. Liu, Z.H. Peng, X.B. Li, Comparison of the effects of Ti- and Si-containing minerals on goethite transformation in the Bayer digestion of goethitic bauxite, Int. J. Miner. Metall. Mater. 30 (9) (2023) 1705-1715.

[20] G.A. Zhou, Z.X. Li, Q.H. Wang, Y.X. Zhu, P. Hua, S.H. Yao, Q.P. Sun, A multi-material cascade elastocaloric cooling device for large temperature lift, Nat. Energy 9 (7) (2024) 862-870.

[21] F. Wang, M. Song, M.N. Elkot, N. Yao, B.H. Sun, M. Song, Z.W. Wang, D. Raabe, Shearing brittle intermetallics enhances cryogenic strength and ductility of steels, Science 384 (6699) (2024) 1017-1022.

[22] A.J. Whitworth, H.E.A. Brand, S.A. Wilson, I.E. Grey, N.R. Stephen, Y. Gozukara, A.J. Frierdich, The occurrence of monoclinic jarosite in natural environments, Am. Mineral. 108 (3) (2023) 584-594.

[23] J. Cuadros, M. Sánchez-Marañón, C. Mavris, S. Fiore, J.L. Bishop, M. Melgosa, Color analysis and detection of Fe minerals in multi-mineral mixtures from acid-alteration environments, Appl. Clay Sci. 193 (2020) 105677.

[24] Z.C. Jian, Y.F. Liu, Y.F. Zhu, J.Y. Li, H.Y. Hu, J.Q. Wang, L.Y. Kong, X.B. Jia, H.X. Liu, J.X. Guo, M.Y. Li, Y.S. Xu, J.F. Mao, S.L. Zhang, Y. Su, S.X. Dou, S.L. Chou, Y. Xiao, Solid-state synthesis of low-cost and high-energy-density sodium layered-tunnel oxide cathodes: dynamic structural evolution, Na⁺/vacancy disordering, and prominent moisture stability , Nano Energy 125 (2024) 109528.

[25] S.H. Zang, A.W. Hauser, S. Paul, G.M. Hocky, S. Sacanna, Enabling three-dimensional real-space analysis of ionic colloidal crystallization, Nat. Mater. 23 (8) (2024) 1131-1137.

[26] M.J. Wang, D.C. Chen, Z. Li, Z.Q. Wang, S.H. Huang, P.Q. Hai, Y.W. Tan, X.D. Zhuang, P. Liu, Epitaxial growth of two-dimensional nonlayered AuCrS₂ materials via Au-assisted chemical vapor deposition , Nano Lett. 24 (7) (2024) 2308-2314.

[27] T. Ikuno, W. Chaikittisilp, Z.D. Liu, T. Iida, Y. Yanaba, T. Yoshikawa, S. Kohara, T. Wakihara, T. Okubo, Structure-directing behaviors of tetraethylammonium cations toward zeolite beta revealed by the evolution of aluminosilicate species formed during the crystallization process, J. Am. Chem. Soc. 137 (45) (2015) 14533-14544.

[28] S. Qiu, T.S. Qiu, H.S. Yan, Q.B. Long, H. Wu, X.B. Li, D.M. Zhu, Investigation of protonation and deprotonation processes of kaolinite and its effect on the adsorption stability of rare earth elements, Colloids Surf. A Physicochem. Eng. Asp. 642 (2022) 128596.

[29] B. Matangouo, G.K. Dedzo, L. Dzene, L. Josien, C.P. Nanseu-Njiki, E. Ngameni, Dodecylamine encapsulation in layered smectite clay mineral: release and application for copper corrosion inhibition in 0.1 M nitric acid solution, J. Phys. Chem. Solids 180 (2023) 111427.

[30] I.A. Nnanwube, M. Keke, O.D. Onukwuli, Assessment of calcined Owhe kaolinite for potential alumina recovery via nitric acid route, Results Chem. 7 (2024) 101262.

[31] A. Minami, P.D. Hu, Y. Sada, H. Yamada, K. Ohara, Y. Yonezawa, Y. Sasaki, Y. Yanaba, M. Takemoto, Y. Yoshida, T. Okubo, T. Wakihara, Tracking sub-nanoscale structural evolution in zeolite synthesis by in situ high-energy X-ray total scattering measurement with pair distribution function analysis , J. Am. Chem. Soc. 144 (51) (2022) 23313-23320.

[32] Y. Chen, Y.D. Liu, L. Li, T. Sakthivel, Z.X. Guo, Z.F. Dai, Intensifying the supported ruthenium metallic bond to boost the interfacial hydrogen spillover toward pH-universal hydrogen evolution catalysis, Adv. Funct. Mater. 34 (28) (2024) 2401452.

[33] X.X. Han, I. Kulaots, X.M. Jiang, E.M. Suuberg, Review of oil shale semicoke and its combustion utilization, Fuel 126 (2014) 143-161.

[34] P. Dong, Y.H. Song, L. Wu, Y. Wang, N. Yin, Y.F. Wang, Y.F. Li, Synergistic removal of organics from semi-coke wastewater by persulfate and cyanide tailings, Sep. Purif. Technol. 333 (2024) 126056.

[35] L.L. Lu, X.Q. Liu, Y. Sun, S.J. Wang, J.T. Liu, S.B. Ge, T.X. Wei, H.Y. Zhang, J.H. Su, Y.Y. Zhang, W. Fan, Silk-fabric reinforced silk for artificial bones, Adv. Mater. 36 (23) (2024) 2308748.

[36] Y. Wu, S.J. Tan, G. Fang, Y.Q. Zhang, G.B. Ji, Manipulating CNT films with atomic precision for absorption effectiveness-enhanced electromagnetic interference shielding and adaptive infrared camouflage, Adv. Funct. Mater. 35 (18) (2025) 2402193.

[37] K. Fan, W.F. Xie, J.Z. Li, Y.N. Sun, P.C. Xu, Y. Tang, Z.H. Li, M.F. Shao, Active hydrogen boosts electrochemical nitrate reduction to ammonia, Nat. Commun. 13 (2022) 7958.

[38] M.X. Ran, B.B. Du, W.Y. Liu, Z.Y. Liang, L.H. Liang, Y.Y. Zhang, L.X. Zeng, M.Y. Xing, Dynamic defects boost in-situ H₂O₂ piezocatalysis for water cleanup , Proc. Natl. Acad. Sci. USA 121 (9) (2024) e2317435121.

[39] X. Liu, J.R. Wang, Y.X. Shang, C.T. Yavuz, N.M. Khashab, Ionic covalent organic framework-based membranes for selective and highly permeable molecular sieving, J. Am. Chem. Soc. 146 (4) (2024) 2313-2318.

[40] J.L. Liu, X.Y. Chen, K.Z. Chen, W.M. Tian, Y.S. Sheng, B. She, Y.Y. Jiang, D.Y. Zhang, Y. Liu, J.H. Qi, K. Chen, Y.M. Ma, Z.X. Qiu, C.Y. Wang, Y.F. Yin, S.L. Zhao, J. Leng, S.Y. Jin, W.S. Zhao, Y.Y. Qin, Y.Q. Su, X.Y. Li, X.J. Li, Y. Zhou, Y.H. Zhou, F.R. Ling, A.Y. Mei, H.W. Han, Electron injection and defect passivation for high-efficiency mesoporous perovskite solar cells, Science 383 (6688) (2024) 1198-1204.

[41] Q. Hu, W.L. Zhou, S. Qi, Q.H. Huo, X. Li, M.Y. Lv, X.B. Chen, C. Feng, J.Y. Yu, X.Y. Chai, H.P. Yang, C.X. He, Pulsed co-electrolysis of carbon dioxide and nitrate for sustainable urea synthesis, Nat. Sustain. 7 (4) (2024) 442-451.

[42] J.H. Liu, Y.S. Huang, Y.Z. Liu, D.C. Zhang, K. Koynov, H.J. Butt, S. Wu, Reconfiguring hydrogel assemblies using a photocontrolled metallopolymer adhesive for multiple customized functions, Nat. Chem. 16 (6) (2024) 1024-1033.

[43] S. Pan, H.Y. Zhou, Q. Wang, J.R. Bai, D. Cui, X.M. Wang, Experimental and molecular simulation studies of Huadian oil shale kerogen, ACS Omega 7 (20) (2022) 17253-17269.

[44] Y. Xu, Y.J. Ma, X.H. Chen, K.Q. Wu, K.Y. Wang, Y.F. Shen, S.Q. Liu, X.J. Gao, Y.J. Zhang, Regulating reactive oxygen intermediates of Fe-N-C SAzyme via second-shell coordination for selective aerobic oxidation reactions, Angew. Chem. Int. Ed. 63 (36) (2024) e202408935.

[45] X.H. Jiang, B.H. Zhou, W.J. Yang, J.Y. Chen, C. Miao, Z.Y. Guo, H. Li, Y. Hou, X.H. Xu, L.Z. Zhu, D.H. Lin, J. Xu, Precise coordination of high-loading Fe single atoms with sulfur boosts selective generation of nonradicals, Proc. Natl. Acad. Sci. USA 121 (4) (2024) e2309102121.

[46] P.V. Lakshminarayanan, H. Toghiani, C.U. Pittman Jr., Nitric acid oxidation of vapor grown carbon nanofibers, Carbon 42 (12-13) (2004) 2433-2442.

[47] X.F. Jiang, H. Huang, Y.F. Chai, T.L. Lohr, S.Y. Yu, W.Z. Lai, Y.J. Pan, M. Delferro, T.J. Marks, Hydrolytic cleavage of both CS₂ carbon-sulfur bonds by multinuclear Pd (II) complexes at room temperature , Nat. Chem. 9 (2) (2017) 188-193.

[48] H. Ullah, A. Siddiqa, A. Ashfaq, B. Younas, M. Demir, M.A. Mansoor, M. Iqbal, Eco-friendly guar gum-montmorillonite composite hydrogels crosslinked with N,N′-methylene bisacrylamide for selective adsorption of methylene blue, crystal violet and safranin, Int. J. Biol. Macromol. 328 (2025) 147687.

[49] Y. Rakhila, A. Elmchaouri, A. Mestari, S. Korili, M. Abouri, A. Gil, Adsorption recovery of Ag(I) and Au(III) from an electronics industry wastewater on a clay mineral composite, Int. J. Miner. Metall. Mater. 26 (6) (2019) 673-680.