Low-cost farmed shrimp shells could remove arsenic from solutions kinetically

Area of Science:

• Environmental Science
• Materials Science
• Chemical Engineering

Background:

• Arsenic (As) contamination in aqueous solutions poses significant environmental and health risks.
• Effective and economical methods for arsenic removal are crucial for water purification.
• Chitinous materials, like shrimp shells, are abundant waste products with potential adsorbent properties.

Purpose of the Study:

• To investigate the efficacy of black tiger shrimp (Penaeus monodon) and white shrimp (Litopenaeus vannamei) shells for arsenic removal from aqueous solutions.
• To analyze the adsorption behavior using experimental data and established isotherm and kinetic models.
• To evaluate the potential of shrimp shells as a sustainable and low-cost sorbent for arsenic remediation.

Main Methods:

• Experimental batch adsorption studies were conducted using shrimp shells as sorbents.
• Sorption capacities were measured and compared between black tiger and white shrimp shells.
• Langmuir, Freundlich isotherm, and pseudo-second-order kinetic models were applied to analyze adsorption data.
• Analysis of Variance (ANOVA) was used to determine significant differences in sorption capacities.

Main Results:

• Sorption capacities for black tiger shrimp shells ranged from 8.1 x 10(-3) to 5.0 x 10(-1) mg/g, and for white shrimp shells from 7.8 x 10(-3) to 2.4 x 10(-1) mg/g.
• No significant difference (P > 0.05) was found in arsenic sorption capacities between the two shrimp species.
• Langmuir and Freundlich isotherm models (r(2) > 0.90) and pseudo-second-order kinetics accurately described the adsorption process, indicating dependence on initial As concentration and retention time.

Conclusions:

• Shrimp shells are a viable, low-cost biosorbent for removing arsenic from aqueous solutions.
• The adsorption process is well-described by Langmuir and Freundlich isotherms and pseudo-second-order kinetics.
• Utilizing shrimp shell waste for arsenic removal offers an economical approach to water treatment and adds value to seafood processing byproducts.