Rice husk is an abundant agricultural by-product generated in massive quantities during the global milling and processing of rice. Generally, this residual solid waste is disposed of through environmentally harmful methods, such as open burning or disposal in landfills, which contribute to pollution and the depletion of landfill space. However, the focus is gradually shifting towards sustainable waste management and circular economy principles. One promising approach is the conversion of rice husk ash into a pozzolanic material for the production of geopolymer foam, transforming an environmental burden into a valuable industrial resource.

This study investigates the optimisation of porous geopolymer foam produced from rice husk ash by systematically evaluating the effects of two chemical additives, namely hydrogen peroxide and sodium alcohol ether sulphate (SAES). In the synthesis of geopolymer foam, each additive performs a distinct function. Hydrogen peroxide acts as the foaming agent. During the reaction, it releases gas that significantly increases the porosity of the material. In contrast, SAES functions as a stabilising agent. Its primary role is to strengthen and stabilise the cellular structure of the foam, ensuring that the newly formed pores remain intact and uniformly distributed.

The geopolymer foam was prepared through a controlled mixing process using sodium silicate and sodium hydroxide as alkaline activators, together with rice husk ash, a silicon-based additive known as Genioperl, hydrogen peroxide, and the SAES stabiliser. The experimental design focused on two independent variables: the concentration of hydrogen peroxide and the concentration of SAES.

Following fabrication, the geopolymer foam samples were subjected to comprehensive testing to determine their total porosity and compressive strength in accordance with established industry standards. The results demonstrated a clear inverse relationship associated with the foaming agent. As the concentration of hydrogen peroxide increased, the total porosity of the foam also increased, while the compressive strength decreased. However, the addition of SAES provided an effective balance by improving the structural integrity of the geopolymer foam. Notably, a concentration of 1.0 wt.% SAES maintained the compressive strength without causing a significant increase in total porosity.

The study concluded that the optimum balance between high total porosity and adequate compressive strength was achieved using a formulation containing 0.40 wt.% hydrogen peroxide and 1.0 wt.% SAES. This research contributes significantly to agricultural science and materials technology by demonstrating the potential of rice husk ash-based geopolymer foam as a sustainable construction material. Furthermore, the findings highlight opportunities for commercialisation, suggesting that the optimised eco-friendly foam can be applied in a wide range of agricultural applications, including farm buildings, agricultural pipeline systems, and other structural components within agricultural environments, thereby supporting the development of greener infrastructure.

Figure 1. Contour plot for the effect of hydrogen peroxide and stabilizer on the total porosity

Figure 2: Contour plot for the effect of hydrogen peroxide and stabilizer on the compressive strength

Source:

Nurul Husna Mohd Azib, Mohd Salahuddin Mohd Basri*, Mohd Zuhair Mohd Nor, Faiqa Shazeaa Mohd. Salleh, Siti Hajar Othman, Mohd Afandi P Mohammed, Norkhairunnisa Mazlan, Siti Hasnah Kamarudin, and Muhammad Hazwan Hamzah.

(http://www.pertanika.upm.edu.my/resources/files/Pertanika%20PAPERS/JST%20Vol.%2033%20(S1)%202025/04%20JST(S)-0682-2025.pdf)

Date of Input: 29/06/2026 | Updated: 29/06/2026 | nurnazeera