Effect of Mangrove Biochar Residue Amended Shrimp Pond Sediment on Nitrogen Adsorption and Leaching

• Main Authors: Sokkeang Be, Soydoa Vinitnantharat, Anawat Pinisakul
• Format: Article
• Language: English
• Published: MDPI AG 2021-06-01
• Series: Sustainability
• Subjects: adsorption isotherm; biochar; nitrogen leaching; nitrogen retention; pond sediment; shrimp farm
• Online Access: https://www.mdpi.com/2071-1050/13/13/7230

Mangrove biochar residue was used for nitrogen adsorption and retention in sediment, which is beneficial for plant germination. The present study investigated the effect of contact time (5–360 min), biochar dosage (0.2–2 g L⁻¹), pH (5–6), and initial concentration (2–10 mg L⁻¹) on NH₄⁺-N and NO₃⁻-N adsorption. Three different adsorption isotherm models were used to fit the experimental data. Column leaching experiments were conducted to investigate the effect of biochar with sediment from a shrimp pond on nitrogen leaching at varying biochar dosages (0–8% <i>w</i>/<i>w</i>). The results showed that the maximum percentage of both NH₄⁺-N and NO₃⁻-N adsorption was achieved at an equilibrium contact time of 240 min, with an adsorbent dosage of 2 g L⁻¹, and pH at 5.5 and 5, respectively. The adsorption of NH₄⁺-N and NO₃⁻-N were fitted to the Freundlich model and the adsorption process followed the physisorption and ion exchange. The addition of 8% biochar reduced both cumulative water volume and nitrogen leaching from the sediment. The biochar amendment increased the relative abundance of nitrifying and denitrifying bacteria in the sediment. This result suggested that biochar amended with sediment could be useful for nitrogen loss reduction.