Optimization and characterization of biodiesel from waste cooking oil using modified CaO catalyst derived from snail shell

Currently, research has diverted toward generating renewable fuels due to the unreliable supply and rising cost of conventional fuels. Biodiesel is renewable fuel commonly obtainable via a simple process. Biodiesel was produced via the transterification of waste cooking oil (WCO) using heterogeneous catalysts. The aim of this study was to synthesis a ZnO and TiO₂-supported CaO catalyst from a snail shell for the transterification of waste cooking palm oil to produce biodiesel. Sol-gel and wet-impregnated methods were adopted to synthesize ZnO and catalyst, respectively. The physicochemical properties of waste cooking oil and biodiesel were characterized in accordance to AOAC and ASTMD standard methods. The FTIR and XRD analyses were carried out to characterize the biodiesel and the prepared catalysts. The result of this study revealed that CaO catalyst derived from snail shall, resulted to a WCO-derived biodiesel yield of 80%. The CaO catalyst modified with ZnO and TiO₂, further led to an increased biodiesel of 90% and 95%, respectively. The result of this study showed that the optimum conditions associated with highest biodiesel yield over the synthesized catalysts were at 3% catalyst weight, 65 °C, a 6:1 methanol-to-oil ratio and 3-h reaction time. The FTIR spectra also proved successful formation of biodiesel. Biodiesel was successfully synthesized from WCO, and the CaO catalyst synthesized from snail shells and modified with ZnO and TiO₂, showed potential to substitute for costly catalysts derived from chemical reagents for biodiesel production.

[Measurement of morphological features of Oncomelania hupensis shells in Yunnan Province]

OBJECTIVE

To investigate the morphological variation of Oncomelania hupensis shells in Yunnan Province, so as to provide insights into the understanding of O. hupensis genetic evolution and control.

METHODS

According to the O. hupensis density, geographical location, altitude, water system and environmental type, 12 administrative villages were sampled from 10 schistosomiasis-endemic counties (districts) in 3 prefectures (cities) of Yunnan Province as snail collection sites. From December 2021 to January 2022, about 200 snails were collected from each collection site, among which thirty adult snails (6 to 7 spirals) were randomly selected from each site, and the 11 morphological indexes of snail shells were measured and subjected to cluster analysis and principal component analysis.

RESULTS

Of O. hupensis snails from 12 localities of Yunnan Province, the longest shell (7.33 mm) was detected in snails from Yongle Village, Eryuan County, with the shortest (4.68 mm) in Dongyuan Village, Gucheng District, and the largest angle of apex (59.47°) was measured in snails from Caizhuang Village, Midu County, with the smallest (41.40°) in Qiandian Village, Eryuan County. The mean coefficient of variation was 9.075% among O. hupensis snails from 12 localities of Yunnan Province, with the largest coefficient of variation seen in the thickness of the labra brim (29.809%). Among O. hupensis snails from 12 localities of Yunnan Province, the mean Euclidean distance was 2.26, with the shortest Euclidean distance seen between O. hupensis snails from Qiandian Village of Eryuan County and Wuxing Village of Dali City (0.26), and the largest found between O. hupensis snails from Caizhuang Village of Midu County and Cangling Village of Chuxiong County (8.17). Cluster analysis and principal component analysis classified O. hupensis snails from 12 localities of Yunnan Province into three categories, including the O. hupensis snail samples from Caizhuang Village of Midu County, O. hupensis snail samples from Cangling Village of Chuxiong County, and O. hupensis snail samples from Qiandian Village of Eryuan County, Wuxing Village of Dali City, Yangwu Village of Yongsheng County, Xiaoqiao Village of Xiangyun County, Yongle Village of Eryuan County, Xiaocen Village of Dali City, Anding Village of Nanjian County, Dongyuan Village of Gucheng District, Lianyi Village of Heqing County, and Dianzhong Village of Weishan County. The variations in these three categories of snail samples were mainly measured in the principal component 2 related to the angle of apex and the thickness of the labra brim.

CONCLUSIONS

The variations in the Euclidean distance and morphological features of shells of O. hupensis from 12 localities of Yunnan Province gradually rise with the decrease in the latitude of the collection sites. The angle of apex is an indicator for the growth of O. hupensis whorl.

Comparative analysis on the bleaching of crude palm oil using activated groundnut hull, snail shell and rice husk

Researchers have found out several ways by which environmental pollution can be of positive relevance by recycling the waste to ensure a cleaner and healthier environment. The bleaching process is a crucial process in palm oil refining in which an adsorbent is majorly used to adsorb the unwanted colour pigments and a wide range of other impurities. This study aims to modify three different adsorbents; Groundnut hull, Snail shell, and rice husk and processed them into powder form as Groundnut hull powder [GHP], Snail shell powder [SSP] and Rice husk powder [RHP] respectively. The effects of three factors: temperature, mass and time were investigated on the response. MINITAB 19 software was employed which resulted in 20 runs. The optimization of the bleaching effects imposed by the adsorbents on palm oil using Central Composite Design (CCD) was evaluated. The free fatty acid and peroxide value decrease with bleaching while the saponification value increased with bleaching. The analysis conducted shows that groundnut hull was able to adsorb the most significant value of FFA and peroxide value in the palm oil. The lowest value of FFA obtained indicates that bleaching increases the shelf life of the oil and makes it more suitable for soap making.

Wettability and dynamics of water droplet on a snail shell

HYPOTHESIS

There are many natural surfaces with special wettabilities. Snail shells have unique rough structures, which indicates a specific wettability. In this study, the surface of a snail shell was simulated using epoxy resins, and water droplet dynamics on original and simulated snail shells were investigated to understand its special wettability.

EXPERIMENTS

The shell of the Euhadra sandai species of snails was used. The surface structure of the snail shell was simulated using epoxy resins. The surface of this EP resin was treated with UV-O₃ for different periods of time. Wettabilities and dynamics of water droplet on the samples were characterized.

FINDINGS

The surface of the snail shell with a water contact angle of approximately 85° caused the droplet to spread, which is the first report of water droplet dynamics on the shell surface. The behavior of a water droplet on the shell transformed from the Cassie state into the Wenzel state. Changes in the contact angle and diameter of the droplet base on the snail shell were larger than those on the epoxy resins. The surface roughness and chemical heterogeneity of the snail shell led to distortion of the three-phase contact line and enhancement of the spreading of the water droplet.

Calcined Umbonium vestiarium snail shell as an efficient adsorbent for treatment of wastewater containing Co (II)

In the present study, the Umbonium vestiarium snail shell (UVS) was used as an abundant and low-cost resource for the removal of Co (II) from aqueous solution. The characteristics of calcined Umbonium vestiarium snail shell (CUVS) were analyzed using FTIR, SEM, MAP, EDAX, and BET analyses. The results showed that the specific surface area of the CUVS was obtained 17.02 m2/g which was an acceptable amount. The presence of Co (II) in the adsorbent structure was confirmed by EDAX, and Map analyses after Co (II) adsorption showed that the adsorbent successfully adsorbed Co (II) from aqueous solution. The effect of different parameters such as, contact time, initial concentration of cobalt ion, the adsorbent dose, and pH value was also investigated. The maximum efficiency of cobalt ion adsorption was measured 93.87% at a pH value of 6, contact time of 80 min, the adsorbent dose of 3 g/L, and initial ion concentration of 10 mg/L. Also, Langmuir, Freundlich, and D-R isotherm models were used to determine the most appropriate isotherm model for cobalt ion adsorption. The adsorption equilibrium data were better fitted with the Langmuir model with a maximum adsorption capacity of 93.46 mg/g. Additionally, the average free energy of adsorption was evaluated in the amount of 1.4085 KJ/mol, revealing a physical adsorption. Moreover, the kinetic behavior study showed that the experimental data follow the pseudo second order kinetic model to the value of correlation coefficient.