DOI: https://doi.org/10.9767/bcrec.20636

Effect of Equimolar Sodium Borohydride-Ferric Chloride Concentrations on Nano Zero-Valent Iron/Palm Shell Composites for Simultaneous Nanogold Recovery and Hydrogen Generation

1Waste Management and Resource Recovery (WeResCue) Group, Faculty of Chemical Engineering, Universiti Teknologi MARA, Cawangan Pulau Pinang, 13500 Permatang Pauh, Penang, Malaysia

2School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, Seri Ampangan, 14300 Nibong Tebal, Seberang Perai Selatan, Pulau Pinang, Malaysia

3Petronas Gas Berhad Level 49-50, Tower 1, Petronas Twin Towers, 50088 Kuala Lumpur, Malaysia

Received: 13 Jan 2026; Revised: 19 Feb 2026; Accepted: 20 Feb 2026; Available online: 8 Mar 2026; Published: 30 Aug 2026.
Editor(s): Istadi Istadi
Open Access Copyright (c) 2026 by Authors, Published by BCREC Publishing Group
Creative Commons License This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
Fulltext View|Download

Citation Format:
Cover Image
Abstract

Gold-containing waste solutions represent both an environmental liability and a valuable secondary resource, yet few existing technologies integrate nanogold recovery with sustainable hydrogen generation from these streams. In this study, the effect of equimolar sodium borohydride–ferric chloride (NaBH₄–FeCl₃) concentrations on the synthesis and performance of nanoscale zero-valent iron (nZVI)/palm shell composites was systematically investigated for the simultaneous recovery of nanogold and generation of hydrogen from gold-containing aqueous solutions. The composites were synthesized at different equimolar NaBH₄–FeCl₃ concentrations (0.5–2.0 M), while maintaining a fixed overall molar ratio, with palm shell biomass employed as a support to suppress particle aggregation and preserve reactive surface area. Nanogold formation was evaluated using UV–Vis spectroscopy via localized surface plasmon resonance, while hydrogen evolution was quantified by a water-displacement method. Surface properties were characterized by BET analysis. Nanogold recovery increased progressively with increasing equimolar precursor concentration, whereas hydrogen production exhibited a non-linear dependence, reaching a maximum of 29.02 mL at 1.5 M, which also corresponded to the highest BET surface area (13.57 m²/g). Further increasing the equimolar NaBH₄–FeCl₃ concentration to 2.0 M led to surface passivation and diminished reactivity. These results demonstrate that equimolar precursor concentration plays a critical role in governing nZVI/palm shell composite structure and functionality. The optimized composite exhibits strong potential as a multifunctional material for integrated precious metal recovery and green hydrogen production, thereby contributing to sustainable circular resource utilization and clean energy technologies. Copyright © 2026 by Authors, Published by BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Keywords: Nano zero-valent iron; Equimolar precursor concentrations; Nanogold recovery; Hydrogen generation; Palm shell composites
Funding: Ministry of Higher Education (MOHE), Malaysia under contract FRGS/1/2023/TK08/UITM/02/5; Ministry of Higher Education (MOHE), Malaysia under contract FRGS/1/2022/TK08/UITM/02/10

Article Metrics:

Article Info
Section: 3rd International Symposium of Reaction Engineering, Catalysis and Sustainable Energy 2025 (RECASE 2025)
Language : EN
Recent articles
Role of Synthesis Route on The Structural and Photocatalytic Activity of Magnetic TUD-1 Coated NiFe2O4 Efficient Adsorption of Tetracycline from Aqueous Solution onto Zinc Oxide Nanoparticles: Isotherm, Kinetic, Regeneration and Thermodynamic Studies Enhanced Photocatalytic Performance and Kinetic Improvement of Reusable W-based POM Composite for Produced Water Treatment 3D/1D Amine Functionalized MIL-125/TiO2 NWs Metal-organic Framework Heterostructures for Solar Stimulated CO2 Reduction to Green Fuels Effect of Sodium Borohydride to Ferric Chloride Molar Ratios on Nanoscale Zero-Valent Iron for Hydrogen Generation from Formic Acid Comparative Assessment of Empirical Coke Deposition Models during n-Butanol Dehydration over a Zeolite-Y-Based Cracking Catalyst Backmatter (Right Transfer Agreement for Publishing Form) Frontmatter (Front Cover, Editorial Team, Indexing, and Table of Contents) More recent articles
  1. Yeh, Y.C., Creran, B., Rotello, V.M. (2012). Gold nanoparticles: Preparation, properties, and applications in bionanotechnology. Nanoscale 4, 1871–1880. DOI: 10.1039/c1nr11188d
  2. Chang, S., Jampang, A. (2023). Enhanced adsorption selectivity of Au(III) over Cu(II) from acidic chloride solutions by chitosan/palm kernel fatty acid distillate/magnetite nanocomposites. International Journal of Biological Macromolecules, 252, 126491. DOI: 10.1016/j.ijbiomac.2023.126491
  3. Rao, M.D., Singh, K.K., Morrison, C.A., Love, J.B. (2020). Challenges and opportunities in the recovery of gold from electronic waste. RSC Advances, 10(8), 4300–4309. DOI: 10.1039/c9ra07607g
  4. Sharma, R., Kim, Y., Lee, E., Lee, H. (2024). Ultrapure gold recovery from electronic waste as nanoparticles immobilized in hydrogel matrix. Chemical Engineering Journal, 499. DOI: 10.1016/j.cej.2024.156539
  5. Wu, Y., Fang, Q., Yi, X., Liu, G., Li, R.W. (2017). Recovery of gold from hydrometallurgical leaching solution of electronic waste via spontaneous reduction by polyaniline. Progress in Natural Science: Materials International, 27(4), 514–519. DOI: 10.1016/j.pnsc.2017.06.009
  6. Chang, S.H., Jampang, A.O.A. (2021). Green extraction of gold(III) and copper(II) from chloride media by palm kernel fatty acid distillate. Journal of Water Process Engineering, 43, 102298. DOI: 10.1016/j.jwpe.2021.102298
  7. Halim, S.F.A., Chang, S.H., Morad, N. (2020). Extraction of Cu(II) ions from aqueous solutions by free fatty acid-rich oils as green extractants. Journal of Water Process Engineering, 33. DOI: 10.1016/j.jwpe.2019.100997
  8. Chang, S.H. (2017). Parametric studies on an innovative waste vegetable oil-based continuous liquid membrane (WVCLM) for Cu(II) ion separation from aqueous solutions. Journal of Industrial and Engineering Chemistry, 50, 102–110. DOI: 10.1016/j.jiec.2017.01.037
  9. Chang, S.H. (2018). A Comparative Study of Batch and Continuous Bulk Liquid Membranes in the Removal and Recovery of Cu(II) Ions from Wastewater. Water, Air, & Soil Pollution, 229(1), 22. DOI: 10.1007/s11270-017-3659-z
  10. Chaurasia, A.K., Mondal, P. (2021). Hydrogen production from waste and renewable resources. In: Hydrogen Fuel Cell Technology for Stationary Applications. IGI Global, pp. 22–46. DOI: 10.4018/978-1-7998-4945-2.ch002
  11. Chang, S.H., Rajuli, M.F. (2024). An overview of pure hydrogen production via electrolysis and hydrolysis. International Journal of Hydrogen Energy, 84, 521–538. DOI: 10.1016/j.ijhydene.2024.08.245
  12. Chen, K.F., Li, S., Zhang, W.X. (2011). Renewable hydrogen generation by bimetallic zero valent iron nanoparticles. Chemical Engineering Journal, 170(2–3), 562–567. DOI: 10.1016/j.cej.2010.12.019
  13. Cheng, Y., Dong, H., Hao, T. (2021). CaCO3 coated nanoscale zero-valent iron (nZVI) for the removal of chromium(VI) in aqueous solution. Separation and Purification Technology, 257 DOI: 10.1016/j.seppur.2020.117967
  14. Ling, L., Huang, X.Y., Zhang, W.X. (2018). Enrichment of Precious Metals from Wastewater with Core–Shell Nanoparticles of Iron. Advanced Materials, 30(17). DOI: 10.1002/adma.201705703
  15. Han, L., yang, L., Wang, H., Hu, X., Chen, Z., Hu, C. (2016). Sustaining reactivity of Fe0 for nitrate reduction via electron transfer between dissolved Fe2+ and surface iron oxides. Journal of Hazardous Materials, 308, 208–215. DOI: 10.1016/j.jhazmat.2016.01.047
  16. Djafari, J., Fernández-Lodeiro, A., García-Lojo, D., Fernández-Lodeiro, J., Rodríguez-González, B., Pastoriza-Santos, I., Pérez-Juste, J., Capelo, J.L., Lodeiro, C. (2019). Iron(II) as a Green Reducing Agent in Gold Nanoparticle Synthesis. ACS Sustainable Chemistry and Engineering, 7(9), 8295–8302. DOI: 10.1021/acssuschemeng.8b06690
  17. Li, S., Li, J., Wang, W., Zhang, W. xian (2019). Recovery of gold from wastewater using nanoscale zero-valent iron. Environmental Science: Nano, 6(2), 519–527. DOI: 10.1039/C8EN01018H
  18. Sayed, M., Khan, A., Rauf, S., Shah, N.S., Rehman, F., A. Al-Kahtani, A., Khan, J.A., Iqbal, J., Boczkaj, G., Gul, I., Bushra, M. (2020). Bismuth-Doped Nano Zerovalent Iron: A Novel Catalyst for Chloramphenicol Degradation and Hydrogen Production. ACS Omega, 5(47), 30610–30624. DOI: 10.1021/acsomega.0c04574
  19. Aminu, I., Nahil, M.A., Williams, P.T. (2020). Hydrogen from Waste Plastics by Two-Stage Pyrolysis/Low-Temperature Plasma Catalytic Processing. Energy and Fuels, 34(9), 11679–11689. DOI: 10.1021/acs.energyfuels.0c02043
  20. Han, Y., Yang, M.D.Y., Zhang, W., Yan, W. (2015). Optimizing synthesis conditions of nanoscale zero-valent iron (nZVI) through aqueous reactivity assessment. Frontiers of Environmental Science and Engineering, 9(5), 813–822. DOI: 10.1007/s11783-015-0784-z
  21. Liou, Y.H., Lo, S.L., Kuan, W.H., Lin, C.J., Weng, S.C. (2006). Effect of precursor concentration on the characteristics of nanoscale zerovalent iron and its reactivity of nitrate. Water Research, 40(13), 2485–2492. DOI: 10.1016/j.watres.2006.04.048
  22. Turabik, M., Simsek, U. (2017). Effect of synthesis parameters on the particle size of the zero valent iron particles. Synthesis and Reactivity in Inorganic Metal-Organic and Nano-Metal Chemistry, 47, 1033–1043. DOI: 10.1080/15533174.2016.1219869
  23. Eljamal, R., Eljamal, O., Khalil, A.M., Aljamal, R., Khalil, A., Saha, B.B., Matsunaga, N. (2017). Effects of sodium borohydride as a reductant on the synthesis of Nano-scale zero-valent iron. Proceedings of International Exchange and Innovation Conference on Engineering & Sciences (IEICES), 39–42. DOI: 10.15017/1906152
  24. Yusuf, S.A., Ismail, S.N.S., Zubairi, M.S.R.M.A., Muthuraman, G., Halim, S.F.A., Chang, S.H. (2025). Hydrogen Production by Formic Acid Decomposition with Nanoscale Zero-Valent Iron (nZVI): Effects of nZVI Dosage, Temperature and Time. Journal of Advanced Research in Fluid Mechanics and Thermal Sciences, 125(1), 158–166. DOI: 10.37934/arfmts.125.1.158166
  25. Prasetyo, I., Mukti, N.I.F., Cahyono, R.B., Prasetya, A., Ariyanto, T. (2020). Nanoporous Carbon Prepared from Palm Kernel Shell for CO2/CH4 Separation. Waste and Biomass Valorization, 11(10), 5599–5606. DOI: 10.1007/s12649-020-01006-4
  26. Singh, A.K., Rarotra, S., Pasumarthi, V., Mandal, T.K., Bandyopadhyay, D. (2018). Formic acid powered reusable autonomous ferrobots for efficient hydrogen generation under ambient conditions. Journal of Materials Chemistry A, 6(19), 9209–9219. DOI: 10.1039/c8ta02205d
  27. Huang, Y.X., Guo, J., Zhang, C., Hu, Z. (2016). Hydrogen production from the dissolution of nano zero valent iron and its effect on anaerobic digestion. Water Research, 88, 475–480. DOI: 10.1016/j.watres.2015.10.028
  28. Li, P., Lv, F., Xu, J., Yang, K., Lin, D. (2021). Separation and Analysis of Nanoscale Zero-Valent Iron from Soil. Analytical Chemistry, 93(29), 10187–10195. DOI: 10.1021/acs.analchem.1c01452
  29. Yang, Y., Guo, J., Hu, Z. (2013). Impact of nano zero valent iron (NZVI) on methanogenic activity and population dynamics in anaerobic digestion. Water Research, 47(17), 6790–6800. DOI: 10.1016/j.watres.2013.09.012
  30. Panda, B.R., Chattopadhyay, A. (2007). Synthesis of Au nanoparticles at “all” pH by H2O2 reduction of HAuCl4. Journal of Nanoscience and Nanotechnology. 1911–1915. DOI: 10.1166/jnn.2007.740
  31. El Mitwalli, O.S., Barakat, O.A., Daoud, R.M., Akhtar, S., Henari, F.Z. (2020). Green synthesis of gold nanoparticles using cinnamon bark extract, characterization, and fluorescence activity in Au/eosin Y assemblies. Journal of Nanoparticle Research, 22(10). DOI: 10.1007/s11051-020-04983-8
  32. Liu, A., Liu, J., Han, J., Zhang, W.-X. (2015). Evolution of Nanoscale Zero-valent Iron (nZVI). Water: Microscopic and Spectroscopic Evidence on the Formation of Nano-and Micro-structured Iron Oxides. Journal of Hazardous Materials, 322, 129–135. DOI: 10.1016/j.jhazmat.2015.12.070
  33. Zhao, Z., Qiu, Y., Lei, B., Zhang, C., Liu, Z., Wang, W., Wang, H., Li, T. (2025). Amorphous Nano Zero-Valent Iron (A-nZVI) Modified by Ethylenediamine for Efficient Dechlorination of Trichloroethylene: Structure, Kinetics, and Mechanism. Catalysts, 15(12). DOI: 10.3390/catal15121173
  34. Hwang, Y.H., Kim, D.G., Shin, H.S. (2011). Effects of synthesis conditions on the characteristics and reactivity of nano scale zero valent iron. Applied Catalysis B: Environmental, 105(1–2), 144–150. DOI: 10.1016/j.apcatb.2011.04.005
  35. Bae, S., Collins, R.N., Waite, T.D., Hanna, K. (2018). Advances in Surface Passivation of Nanoscale Zerovalent Iron: A Critical Review. Environmental Science and Technology, 52(21), 12010–12025. DOI: 10.1021/acs.est.8b01734
  36. Pang, H., Zhang, E., Zhang, D., Wang, X., Zhao, B., Liu, L., Ma, X., Song, G., Yu, S. (2022). Precursor impact and mechanism analysis of uranium elimination by biochar supported sulfurized nanoscale zero-valent iron. Journal of Environmental Chemical Engineering, 10(2) DOI: 10.1016/j.jece.2022.107288
  37. Chang, S.H., Jampang, A.O.A., Din, A.T.M. (2025). Adsorption isotherms, kinetics, and thermodynamics of Au(III) on chitosan/palm kernel fatty acid distillate/magnetite nanocomposites. International Journal of Biological Macromolecules, 304, 140913. DOI: 10.1016/j.ijbiomac.2025.140913

Last update:

No citation recorded.

Last update:

No citation recorded.