This research offers a novel approach of free chemical preparation to obtain algae-based biopolyol through a ball milling method. The algae-based polyurethane (AlgPU) film was obtained from a casting solution made of ball-milled algal polyol particle and methylene diphenyl diisocyanate (MDI). The characteristics of the material had been investigated using Fourier Transform Infrared, Scanning Electron Microscopy – Electron Dispersive Spectroscopy, Differential Scanning Calorimetry, and Tensile Strength Analysis. The surface area was determined by Brunauer–Emmett–Teller (BET) isotherm, meanwhile the total pore volume was by Barrett-Joyner-Halenda (BJH) isotherm, based on the adsorption-desorption of N 2 . The addition of activated carbon contributed in the increase of functional group and surface area, which were important for the NH 3 –N removal. As a result, the adsorption capacity increased greatly after the addition of activated carbon (from 187.84 to 393.43 μg/g). The results also suggested AlgPU as a good matrix for immobilizing activated carbon filler. The adsorption shows a better fit with Langmuir isotherm model, with R 2 = 0.97487 and root-mean-square error (RMSE) = 33.91952, compared to Freundlich isotherm model (R 2 = 0.96477 and RMSE = 44.05388). This means the NH 3 –N adsorption followed the assumption of homogenous and monolayer adsorption, in which the maximum adsorption was found to be 797.95 μg/g. This research suggests the potential of newly developed material for NH 3 –N removal.

Preparation of magnetic chitosan for mercury removal from polluted water had been conducted. Magnetic particles (Fe 3 O 4) were isolated from local iron sand to provide magnetic properties of chitosan. Glutaraldehyde was used as crosslinking agent of chitosan. The obtained magnetic chitosan was characterized by using FTIR, TGA, DSC, XRD, and SEM. Adsorption experiments were conducted with various contact time, pH and initial concentration of mercury. The results showed glutaraldehyde and Fe 3 O 4 decreased crystallinity of chitosan. Low crystallinity of polymer is favorable for adsorption due to the high accessibility of adsorbate to reach active sites of adsorbent. FTIR and SEM confirmed the formation of magnetic chitosan. Based on correlation coefficient (R 2) values, the adsorption mercury by magnetic chitosan fitted with Langmuir and Freundlich isotherm models.

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Palm and coconut shells are among the most common feed materials for activated carbon manufacturing. Activated carbon is an excellent adsorbent for palm oil mill effluent (POME), especially for the removal of chemical oxygen demand (COD). Palm shell-based activated carbon (PAC) and coconut shell-based activated carbon (CAC) have been prepared through carbonization and followed by an activation process using H2SO4 2.5 M. Both PAC and CAC have lower contents of moisture, fly ash, and ash than that of Indonesian national standard thresholds. The COD removal from POME was performed with the batch adsorption method, where it reached adsorption saturation after 45 minutes of stirring time and optimum removal at pH 3. Isotherm studies suggest that the COD removal using PAC and CAC fit the theoretical data from the Langmuir isotherm model (R2 > 0.99) with Qm of 854.701 and 826.446 mg/g, respectively. The investigation also indicates that PAC has a better performance in COD removal, which has been justified by the elucidation using Fourier Transform-Infrared (FT-IR) and Scanning Electron Microscopy – Electron Dispersive Spectroscopy (SEM-EDS) technique.