Evaluation of Sugarcane Bagasse as a Biosorbent for Arsenic Removal from Groundwater in Mórrope, Peru

Abstract

The presence of arsenic in groundwater poses a significant threat to public health, particularly in rural areas lacking access to treatment technologies. In Mórrope, concentrations exceeding regulatory limits have been detected, necessitating sustainable solutions. The objective of this study was to evaluate the efficiency of sugarcane bagasse as a biosorbent material for removing arsenic from contaminated waters in the Mórrope-Lambayeque district. The experimental design employed a 2 × 3 × 3 factorial design, encompassing three variables: adsorbent dosage (1 and 2 g/L), pH (5, 7, and 9), and initial arsenic concentration (2.5, 4.5, and 6.5 mg/L). The bagasse underwent a series of processing steps, including acid washing, drying, and sieving, and was applied in batch tests. The analysis encompassed removal efficiency, adsorption capacity, isotherm adjustment, and kinetics. The system attained a maximum removal rate of 27.43% with a biosorbent dosage of 2 g/L, pH 9, and an initial arsenic concentration of 2.5 mg/L. The Langmuir model (R2 = 0.9926) provided the most suitable description of the adsorption process, indicating the presence of a monolayer. The adsorption kinetics were best described by the pseudo-second-order model (R2 = 0.9727). However, this statistical fit was not interpreted as definitive evidence of an exclusively chemisorption-controlled mechanism, since surface interactions, external mass transfer, and intraparticle diffusion may contribute simultaneously to arsenic uptake. The results indicate that chemically modified sugarcane bagasse exhibits a measurable but limited capacity for arsenic adsorption. However, the maximum removal efficiency of 27.43% is insufficient for direct drinking-water treatment, and the material should not be considered a stand-alone remediation technology under the evaluated conditions. Further surface modification, process optimization, and integration with complementary treatment stages are required before practical implementation can be considered. Beyond its technical feasibility, this approach holds strong social relevance, as it promotes the use of locally available agricultural residues to improve water quality in vulnerable communities, fostering low-cost, community-managed, and environmentally sustainable solutions for safe water access. Although the removal efficiency remains moderate, future research should aim to enhance adsorption performance and evaluate the potential for large-scale implementation in rural water treatment systems.