Search Results (9)

A scaffold that replicates the physicochemical composition of bone at the nanoscale level is a promising replacement for conventional bone grafts such as autograft, allograft, or xenograft. However, its creation is still a major challenge in bone tissue engineering. The fabrication of a fibrous PVA-HA/Sr matrix made of strontium (Sr)-substituted hydroxyapatite from the shell of Pomecea canaliculate L. (golden apple snail) is reported in this work. Since the fabrication of HAp from biogenic resources such as the shell of golden apple snail (GASs) should be conducted at very high temperature and results in high crystalline HAp, Sr substitution to Ca was applied to reduce crystallinity during HAp synthesis. The resulted HAp and HA/Sr nanoparticles were then combined with PVA to create fibrous PVA-HAp or PVA-HA/Sr matrices in 2 or 4 mol % Sr ions substitution by electrospinning. The nanofiber diameter increased gradually by the addition of HAp, HA/Sr 2 mol %, and HA/Sr 4 mol %, respectively, into PVA. The percentage of the swelling ratio increased and reached the maximum value in PVA-HA/Sr-4 mol %, as well as in its protein adsorption. Furthermore, the matrices with HAp or HA/Sr incorporation exhibited good bioactivity, increased cell viability and proliferation. Therefore, the fibrous matrices generated in this study are considered potential candidates for bone tissue engineering scaffolds. Further in vivo studies become an urgency to valorize these results into real clinical application. Full article

The shell of viviparid snail extract (SVSE) was prepared by a simple and environmentally friendly hydrolysis method and the corrosion inhibition of carbon steel (CS) by SVSE in 1 M HCl was investigated. HPLC and FTIR analysis showed that the main component of SVSE was a mixture of various amino acids. The results of electrochemical and surface analysis showed that SVSE is a hybrid corrosion inhibitor with a corrosion inhibition efficiency of 95.23%. In addition, the adsorption behavior of SVSE on CS surfaces was also investigated in depth by adsorption isotherms, quantum chemistry (QC) and molecular dynamics simulations (MDS). Full article

Sea material is becoming increasingly popular and widely used as an adsorbent in wastewater treatment. Snail shell, a low-cost and natural animal waste material, has been shown to have a high calcium content (>99%) and a large potential surface area for the development of sustainable adsorbents. This paper presents a novel synthesis of methods for using snail shell absorbent materials in the treatment of wastewater containing heavy metals, textile dyes, and other organic substances. Modified biochar made from snail shells has gained popularity in recent years due to its numerous benefits. This paper discusses and analyzes modification methods, including impregnating with supplements, combining other adsorbents, synthesis of hydroxyapatite, co-precipitation, and the sol–gel method. The analysis of factors influencing adsorption efficiency revealed that pH, contact time, temperature, initial concentration, and adsorbent dose all have a significant impact on the adsorption process. Future research directions are also discussed in this paper as a result of presenting challenges for current snail adsorbents. Full article

Activated carbon has been used to treat organic dyes in water systems; however, the adsorption capacity of the samples studied was limited by the specific surface area and influenced by the pH of the aqueous solution. In this study, a hybrid adsorbent consisting of a mixture (MCS) of activated chestnut shell biochar (CN) and pyrolyzed snail shell material (SS) was developed to solve this problem, with the waste snail shell samples being processed by pyrolysis and the chestnut shell samples chemically pretreated and then pyrolyzed. The BET and SEM results revealed that the SS had a mesoporous fluffy structure with a higher specific surface (1705 m²/g) and an average pore diameter of about 4.07 nm, providing a large number of sites for adsorption. In addition, XPS and FTIR results showed that the main component of SS was calcium oxide, and it also contained a certain amount of calcium carbonate, which not only provided an alkaline environment for the adsorption of biochar but also degradation and photocatalytic capabilities. The results showed that the MCS3-1 sample, obtained when CN and SS were mixed in the ratio of 3:1, had good capacity for adsorption for methylene blue (MB), with 1145 mg/g at an initial concentration of 1300 mg/L (92% removal rate). The adsorption behaviors were fitted with the pseudo-second-order kinetic model and Freundlich isotherm model, which indicated that the adsorption was multilayer chemisorption with a saturated adsorption capacity of 1635 mg/g. The photocatalytic capacity from the SS composition was about 89 mg/g, and the sorption of MB dye onto the sorbent reached equilibrium after 300 min. The results suggested that MCS3-1 has enormous potential for removing MB from wastewater. Full article

Snail shells (Anadora Fulica) calcined at different temperatures were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, thermal analyses (TG-DTG), scanning electron microscopy (SEM) and N₂ adsorption–desorption experiments (surface area measurements were found using the coupled BET/BJH method). The principal objective was to identify different forms of calcium carbonate and calcium hydroxide in snail shells as raw materials. The calcium hydroxide thus obtained was used in the synthesis of the hydroxyapatite/L-lysine (HA/Lys) composite. The composite used to chemically modify a glassy carbon electrode (GCE) was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). It appeared that the developed sensor Lys/HA/GCE facilitated electronic transfer compared to the pristine electrode. In a strongly acid medium, this surface protonated and therefore became positively charged, which allowed it to have a good affinity with [Fe(CN)₆]^3-. An application in toluidine blue (TB) electroanalysis in the phosphate buffer was carried out. Optimal sensor performances were obtained using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The performance of the sensor was determined in the concentration range 1 to 10 µM of TB, and the limit of detection (LOD) obtained by the S/N = 3 method was 2.78 × 10⁻⁷ M. The sensor was also used to detect the TB in spring water at 96.79% recovery. Full article

Carbonated hydroxyapatite (CHAp) adsorbent material was prepared from Achatina achatina snail shells and phosphate-containing solution using a wet chemical deposition method. The CHAp adsorbent material was investigated to adsorb aqua Fe(II) complex; [Fe(H₂O)₆]²⁺ from simulated iron contaminated water for potential iron remediation application. The CHAp was characterized before and after adsorption using infrared (IR) and Raman spectroscopy. The IR and the Raman data revealed that the carbonate functional groups of the CHAp adsorbent material through asymmetric orientation in water bonded strongly to the aqua Fe(II) complex adsorbate. The adsorption behaviour of the adsorbate onto the CHAp adsorbent correlated well to pseudo-second-order kinetics model, non-linear Langmuir and Freundlich model at room temperature of a concentration (20–100 mg L⁻¹) and contact time of 180 min. The Langmuir model estimated the maximum adsorption capacity to be 45.87 mg g⁻¹ whereas Freundlich model indicated an S-type isotherm curvature which supported the spectroscopy revelation. Full article

Pb²⁺ is considered to be a very toxic pollutant in the aquatic environmental media. Biopolymeric chitosan synthesized from snail shell has been studied for its potential to remove heavy metals from aqueous solution. The experiments were conducted in the range of 1–50 mg/L initial Pb²⁺ concentration at 298 K. The effects of pH, adsorbent dosage and contact time on the adsorptive property of the adsorbent were investigated and optimized. The derived chitosan was characterized using Fourier transform infrared spectrometer (FT-IR) and X-ray florescence (XRF). The experimental data obtained were analysed using the Langmuir and Freundlich adsorption isotherm models. The Langmuir model and pseudo second order kinetic model suitably described the adsorption and kinetics of the process with regression coefficient of 0.99 and 1.00, respectively. Sodium hydroxide was a better desorbing agent than hydrochloric acid and de-ionized water. From the results obtained, it is concluded that synthesized biopolymers from land snail shells has the potential for the removal of Pb²⁺ from aqueous solutions. Full article

Metaldehyde is a selective pesticide applied to control snails and slugs and which, particularly when application rates are high and during periods of high rainfall, may find its way into water courses, some of which may be used as drinking water supplies. Existing water treatment processes have been inadequate for reducing metaldehyde residual levels (up to 8 µg/L) found in some waters to below the EU/UK statutory limit of 0.1 µg/L. Here a novel coupled adsorption and electrochemical regeneration technology is tested to determine if it is capable of effectively removing metaldehyde. We demonstrate that metaldehyde is not only adsorbed on the adsorbent used but is also destroyed during the regeneration stage, resulting in residual metaldehyde concentrations below the EU/UK regulatory limit for drinking water. No known harmful breakdown by-products were observed to be generated by the process. The effectiveness of the process seems unaffected by organic-rich peat water, indicating the potential for the treatment of drinking water much of which in the UK is derived from upland peaty catchments. Furthermore, successive spiking experiments showed that this technology has the potential to be applied as a continuous process without the generation of substantial waste products. Full article