Introduction: Ammonia, a harmful chemical compound, may cause luminescent shrimp and high mortality by triggering shrimp disease, especially from the bacterium Vibrio harveyi. This study investigated three different raw materials as adsorbents produced by fast pyrolysis to reduce ammonia levels in shrimp ponds by adsorption.
Methods: Corncobs, empty palm bunches (EPB), and coconut shells were carbonized by fast pyrolysis at 350, 450, and 550 °C. Characterization analyses included surface area and porosity (BET), morphology (SEM), and functional groups (FTIR). Batch adsorption experiments were conducted under varying pH conditions (pH 6–9) and at different adsorbent dosages (0.4, 0.6, and 0.8 g). Adsorption behavior was evaluated using the Langmuir and the Freundlich isotherm models, as well as kinetic models to determine the adsorption mechanism.
Results: It was revealed that ammonia adsorption was favorable at basic pH. The adsorption uptake was found to increase with the temperature of pyrolysis and contact time, but decrease with the adsorbent dosages. The pseudo-second-order model exhibited the best fit for the kinetic studies, indicating that the chemisorption process limits ammonia adsorption. The Langmuir model best describes the uptake of ammonia, implying that the adsorption of ammonia onto EPBs-char in this study is homogeneous in a monolayer.
Conclusion: All three activated carbons effectively reduced ammonia levels and pH. The alternative activation solution needs to be considered in the future; strong acids will actually add to new waste. Activated-char modifications also need to be developed, taking into account environmentally friendly materials.