Arsenic bioadsorption from groundwater using Guadua angustifolia Kunth flour

Introduction. Arsenic in groundwater requires low-cost treatment options suitable for decentralised application. Objetives. This study evaluated total arsenic bioadsorption from groundwater using Guadua angustifolia Kunth flour, considering biosorbent dose, contact time, removal efficiency and adsorption capacity. Materials and Methods. Culms were processed by drying, milling and sieving without chemical activation. Batch assays were performed with 250 mL of groundwater containing 0.081 mg L-1 arsenic. A 4 x 3 quantitative factorial design tested 1, 3, 6 and 10 g L-1 flour at 30, 60 and 90 min, with duplicate runs. Final arsenic, removal and adsorption capacity were calculated, followed by factorial analysis of variance, Tukey comparison and quadratic regression. Results. Final arsenic decreased as dose and time increased. The best experimental condition, 10 g L-1 and 90 min, reached 0.008 ± 0.001 mg L-1 and 90.13 ± 0.70% removal. The factorial model was significant, and the quadratic model showed high predictive performance, with no significant lack of fit. Numerical optimisation predicted 9.5965 g L-1 and 86.4404 min for 0.008 mg L-1. Conclusions. Guadua flour showed operational potential as a minimally processed biosorbent for reducing arsenic in groundwater within the tested domain.引言。地下水中的砷亟需适配分散式应用场景的低成本处理方案。研究目标。本研究以狭叶瓜多竹（Guadua angustifolia Kunth）粉为生物吸附剂，评估其对地下水中总砷的吸附效果，考察了生物吸附剂投加量、接触时间、砷去除效率与吸附容量。材料与方法。竹秆经干燥、粉碎与过筛处理，未进行化学活化。采用250 mL砷浓度为0.081 mg·L⁻¹的地下水开展批量吸附实验。设置4×3定量析因设计，分别以1、3、6、10 g·L⁻¹的竹粉投加量，在30、60、90 min的接触时间下进行实验，每组设置平行重复。通过计算最终砷浓度、去除率与吸附容量，随后开展析因方差分析、Tukey多重比较与二次回归分析。结果。随着吸附剂投加量与接触时间的增加，水中剩余砷浓度逐渐降低。最优实验条件为10 g·L⁻¹投加量与90 min接触时间，此时剩余砷浓度为0.008 ± 0.001 mg·L⁻¹，砷去除率达90.13 ± 0.70%。析因模型具有统计学显著性，二次模型展现出较高的预测性能，且无显著失拟现象。数值优化预测，当目标剩余砷浓度为0.008 mg·L⁻¹时，最优吸附剂投加量为9.5965 g·L⁻¹，最优接触时间为86.4404 min。结论。狭叶瓜多竹粉作为一种低加工程度的生物吸附剂，在本实验考察的参数范围内具备降低地下水中砷含量的应用潜力。