From Palm Waste To Carbon Catcher: Malaysian Scientists Turn Agricultural Leftovers Into High-performance CO₂ Spongeg

Biochar Editorial Office, Shenyang Agricultural University

In Malaysia, one of the world's top producers of palm oil, millions of tons of oil palm ash (OPA) are left behind as agricultural waste every year—a disposal challenge that could soon become a climate solution. Now, groundbreaking research from Universiti Sains Malaysia (USM) shows that this humble byproduct can be transformed into a powerful, eco-friendly material capable of capturing carbon dioxide from the air. Published on August 18, 2025, in Carbon Research as an open-access original article, this innovative study was led by Dr. Azam Taufik Mohd Din from the School of Chemical Engineering at Universiti Sains Malaysia's Engineering Campus in Nibong Tebal, Penang. The team didn't just repurpose waste—they engineered it. By treating raw oil palm ash with acid, then subjecting it to carbonization and chemical activation using potassium hydroxide (KOH), they created a new material dubbed OPA-KOH(1:2). The result? A tailor-made adsorbent with a highly optimized mesoporous structure—pores so precisely shaped that they allow CO₂ molecules to flow in easily and stick effectively. Despite having a modest surface area of 30.95 m²/g—far lower than many commercial activated carbons—the material achieved an impressive CO₂ adsorption capacity of 2.9 mmol/g. That performance rivals or even exceeds more expensive materials with much higher surface areas, proving that pore architecture matters more than size alone. "This isn't just recycling—it's upcycling at the molecular level," says Dr. Mohd Din. "We're taking a waste product that often ends up in landfills and turning it into a high-performance tool for carbon capture."

How It Works: Small Pores, Big Impact

The secret lies in the structure. With an average pore size of 72.71 Å, OPA-KOH(1:2) creates an ideal environment for CO₂ molecules to enter quickly and bind efficiently. Comprehensive analysis revealed that adsorption is exothermic and spontaneous, primarily driven by physisorption—a process where CO₂ sticks to the surface through weak physical forces—supported by a minor contribution from weak chemisorption, enhancing overall stability. This dual mechanism means the material can capture CO₂ effectively under realistic conditions, making it a promising candidate for real-world carbon capture, utilization, and storage (CCUS) systems.

Machine Learning Meets Materials Science

What sets this study apart is its fusion of experimental science with artificial intelligence. Recognizing that traditional modeling has limits, the team deployed machine learning (ML) algorithms to predict CO₂ adsorption behavior. Among several models tested, a bilayered neural network (NN) emerged as a star performer—achieving an astonishing R² value greater than 0.99, meaning it predicted experimental outcomes with near-perfect accuracy. "This shows ML isn't just a trend—it's becoming essential," explains Dr. Mohd Din. "It allows us to simulate, optimize, and understand adsorption processes faster and more deeply than ever before." The successful integration of ML opens doors for accelerating the design of next-generation adsorbents, reducing trial-and-error in the lab, and scaling up sustainable technologies more efficiently.

A Win for Sustainability and Industry

Malaysia produces over 20 million tons of palm oil annually—generating vast amounts of residue. By converting oil palm ash, a problematic waste, into a valuable carbon-capture material, this research offers a closed-loop, circular economy solution. It also presents a cost-effective alternative to synthetic adsorbents, which are often energy-intensive to produce and expensive to deploy at scale. "Sustainable doesn't have to mean less effective," says Dr. Mohd Din. "Our work proves that green materials can compete—and win—on performance."

Spotlight on Universiti Sains Malaysia's Leadership

This study highlights the growing strength of the School of Chemical Engineering at Universiti Sains Malaysia in advancing clean energy and environmental technologies. Located on the Engineering Campus in Nibong Tebal, Penang, the school is emerging as a regional hub for innovation in waste valorization, carbon management, and AI-driven chemical engineering.

Dr. Azam Taufik Mohd Din's leadership exemplifies how local solutions—rooted in regional resources and global science—can contribute to planetary challenges.

The Road Ahead: Scaling Up the Solution

The success of OPA-KOH(1:2) paves the way for pilot-scale testing in flue gas treatment, biogas upgrading, and direct air capture systems. Future work will explore regeneration cycles, long-term stability, and integration into industrial processes. With climate targets tightening worldwide, affordable and scalable CCUS technologies are urgently needed. This research delivers both a material and a method: a low-cost, high-efficiency adsorbent born from biomass waste, guided by the predictive power of machine learning. So the next time you enjoy a product containing palm oil, remember: from that same industry's waste, scientists in Malaysia are building a cleaner future—one CO₂ molecule at a time.

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  • Title: Enhanced CO2 capture using KOH-functionalized oil palm ash adsorbent: experimental and applied machine learning approach
  • Keywords: Carbon dioxide adsorption; Oil palm ash-based adsorbent; KOH activation; Machine learning; Bilayered neural network model
  • Citation: Mohamed Saleh, S.N., Rohman, F.S., Muhammad, D. et al. Enhanced CO2 capture using KOH-functionalized oil palm ash adsorbent: experimental and applied machine learning approach. Carbon Res. 4, 60 (2025). https://doi.org/10.1007/s44246-025-00227-3

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About Carbon Research

The journal Carbon Research is an international multidisciplinary platform for communicating advances in fundamental and applied research on natural and engineered carbonaceous materials that are associated with ecological and environmental functions, energy generation, and global change. It is a fully Open Access (OA) journal and the Article Publishing Charges (APC) are waived until Dec 31, 2025. It is dedicated to serving as an innovative, efficient and professional platform for researchers in the field of carbon functions around the world to deliver findings from this rapidly expanding field of science. The journal is currently indexed by Scopus and Ei Compendex, and as of June 2025, the dynamic CiteScore value is 15.4.

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