A Simple One-Step Modification of Shrimp Shell for the Efficient Adsorption and Desorption of Copper Ions

Abstract

Removing toxic heavy metal species from aqueous solutions is a point of concern in our society. In this paper, a promising biomass adsorbent, the modified waste shrimp shell (MS), for Cu (II) removal was successfully prepared using a facile and simple one-step modification, making it possible to achieve high-efficiency recycling of the waste NaOH solution as the modification agent. The outcome shows that with the continuous increase in pH, temperature and ion concentration, the adsorption effect of MS on Cu (II) can also be continuously improved. Adsorption isotherm and adsorption kinetics were fitted with the Langmuir isotherm model and the pseudo-second-order model, respectively, and the maximum adsorption capacity of Cu (II) as obtained from the Langmuir isotherm model fitting reached 1.04 mmol/g. The systematic desorption results indicated that the desorption rate of Cu (II) in the MS could reach 100% within 6 min, where HNO3 is used as the desorption agent. Moreover, experiments have proven that after five successive recycles of NaOH as a modifier, the adsorption capacity of MS on Cu (II) was efficient and stable, maintaining tendency in 0.83–0.85 mmol/g, which shows that waste NaOH solution can be used as a modification agent in the preparation of waste shrimp shell adsorbent, such as waste NaOH solution produced in industrial production, thereby making it possible to turn waste into renewable resources and providing a new way to recycle resources.

Modified Shrimp-Based Chitosan as an Emerging Adsorbent Removing Heavy Metals (Chromium, Nickel, Arsenic, and Cobalt) from Polluted Water

“…The adsorptions of Co 2+ and Ni 2+ in a mixture were 28.84% and 53.57%, respectively, which are lower compared to individual exposure. Like previous reports [30,38,47], we also observed a faster initial removal rate followed by a slower biosorption of ions, which could be due to the accessibility of the binding sites on the MSS surface occupied by the metal ions at the initial phages. Therefore, 30 min could be considered the optimum contact time for removing the Cr 6+ , Ni 2+ , As 5+ , and Co 2+ using MSS in an aqueous solution.…”

“…The adsorptions of Co 2+ and Ni 2+ in a mixture were 28.84% and 53.57%, respectively which are lower compared to individual exposure. Like previous reports [30,38,47], we also observed a faster initial removal rate followed by a slower biosorption of ions, which could be due to the accessibility of the binding sites on the MSS surface occupied by the the binding sites for metals [45,69]. With the increasing amount of MSS (2.5 mg to 12.5 mg), the removal capacity of As 5+ is increased from 43.14% to 89.10%.…”

“…However, many washing steps were involved in the demineralization, deproteinization, decolorization, and deacetylation, which may affect the chitosan yield. Several studies have extracted chitin from shrimp shells and obtained different yield percentages [4,47,48]. In this study, the yield percentages differed from previously reported studies, which may be due to varying conditions, such as the washing steps and using different acid and base concentrations.…”

“…At higher magnifications of 500×, 1000×, and 2000×, the MSS displayed irregular shapes, with more small chips and uneven surface, showing many small hills and valleys with varying shapes in the presence of the metals (Figure 3a-c). Furthermore, the structure of the MSS treated with metals showed a distinct network structure and exhibited clear porous structures, suggesting that most of the protein and fat on the surface had been removed [47] and were favorable for metal adsorption [49]. EDS analysis of MSS following exposure to metal solutions revealed that the element composition of the chitin and chitosan consisted of carbon (C), nitrogen (N), and oxygen (O).…”

Eco-friendly and safe alternatives for the valorization of shrimp farming waste

“…The bigger pore size of the nanowhiskers than chitin and the rod shape of the nanowhiskers could have contributed to the higher dye removal ability of the chitin nanowhiskers (Druzian et al 2019 ). Apart from dyes, SW-derived products have shown the potential to adsorb various heavy metals such as arsenic, chromium, copper, lead, zinc, iron, and nickel (Somerville and Norrström 2009 ; Mohanasrinivasan et al 2014 ; Rech et al 2019 ; Liu et al 2021a ).…”