In response to the growing incidents of marine pollution, a novel material with a sustainable source is in demand. Dry marine microalgae isolated from the Indonesian marine environment provide a viable and sustainable biomass source for addressing this issue. This study aims to investigate the removal capability of the dry marine microalgae biomass and their modified version using zero-valent iron (ZVI) particles in removing dissolved Cd. The modification of dry biomass using ZVI was carried out using the reduction method by NaBH4. SEM-EDS, FTIR, and XRD showed variation in the biosorbent characteristic. The biosorbent of Chaetoceros sp. (C), Nitzschia sp. (N), Tetraselmis sp. (T), and their modified version C-ZVI, N-ZVI, and T-ZVI exhibited a slight reduction in removal capability at pH 7–4. The removal capabilities are higher at lower initial concentrations of Cd and decrease at higher concentrations of Cd. The removal capabilities of each biosorbent increase as a function of contact time. The highest removal of Cd is observed by C-ZVI at pH 7 (96.8 ± 0.8%), T-ZVI at 5 mg.L−1 initial Cd concentration (97.9 ± 2.3%), and N-ZVI at 300 min (96.7 ± 1.1%). Considering error functions computation, The Dubinin-Radushkevich (D-R) isotherm model is the most representative of experimental data. The D-R isotherm model indicated that T-ZVI had the highest maximum adsorption capacity (<InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="42250_2025_1194_Article_IEq1.gif" Format="GIF" Height="17" Rendition="HTML" Resolution="72" Type="Linedraw" Width="28" /> </InlineMediaObject> <EquationSource Format="TEX">${Q}_{m}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>Q</mi> <mi>m</mi> </msub> </math></EquationSource> </InlineEquation>) = 38.9 mg.g−1. Meanwhile, the pseudo-second-order is the most fitted model for the experimental data, with N-ZVI being the highest adsorption capacity at equilibrium (<InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="42250_2025_1194_Article_IEq2.gif" Format="GIF" Height="17" Rendition="HTML" Resolution="72" Type="Linedraw" Width="23" /> </InlineMediaObject> <EquationSource Format="TEX">${Q}_{e}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>Q</mi> <mi>e</mi> </msub> </math></EquationSource> </InlineEquation>) = 10.05 mg.g−1. Thus, this study suggested that modifying dry marine biomass using ZVI improves the adsorption capability of Cd.

Modification of Dry Marine Green Microalgae and Marine Diatom Biomass Using Zero-Valent Iron Particle for Cd Removal: Isotherm and Kinetic Study

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发表日期：

2025年2月1日

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Harmesa,
Lestari,
Sandi Permadi,
Asep Bayu,
Fitri Budiyanto

摘要

In response to the growing incidents of marine pollution, a novel material with a sustainable source is in demand. Dry marine microalgae isolated from the Indonesian marine environment provide a viable and sustainable biomass source for addressing this issue. This study aims to investigate the removal capability of the dry marine microalgae biomass and their modified version using zero-valent iron (ZVI) particles in removing dissolved Cd. The modification of dry biomass using ZVI was carried out using the reduction method by NaBH₄. SEM-EDS, FTIR, and XRD showed variation in the biosorbent characteristic. The biosorbent of Chaetoceros sp. (C), Nitzschia sp. (N), Tetraselmis sp. (T), and their modified version C-ZVI, N-ZVI, and T-ZVI exhibited a slight reduction in removal capability at pH 7–4. The removal capabilities are higher at lower initial concentrations of Cd and decrease at higher concentrations of Cd. The removal capabilities of each biosorbent increase as a function of contact time. The highest removal of Cd is observed by C-ZVI at pH 7 (96.8 ± 0.8%), T-ZVI at 5 mg.L⁻¹ initial Cd concentration (97.9 ± 2.3%), and N-ZVI at 300 min (96.7 ± 1.1%). Considering error functions computation, The Dubinin-Radushkevich (D-R) isotherm model is the most representative of experimental data. The D-R isotherm model indicated that T-ZVI had the highest maximum adsorption capacity ( ${Q}_{m}$ $Q_{m}$ ) = 38.9 mg.g⁻¹. Meanwhile, the pseudo-second-order is the most fitted model for the experimental data, with N-ZVI being the highest adsorption capacity at equilibrium ( ${Q}_{e}$ $Q_{e}$ ) = 10.05 mg.g⁻¹. Thus, this study suggested that modifying dry marine biomass using ZVI improves the adsorption capability of Cd.