Ultrasonic high-yield extraction of non-toxic fucose-containing Abroma augusta polysaccharide bearing emulsifying properties.

BACKGROUND: The stem of Abroma augusta contains mucilaginous polysaccharides having numerous ethnomedicinal properties. The present work aimed to develop a scalable ultrasonic-assisted aqueous Abroma augusta mucilage (AAM) extraction (UAE) method and further explores its emulsifying property and toxicity concern. RESULTS: The combination of ultrasonic power (750 W), solid-to-liquid ratio (1:15) and temperature (348 K) gave the highest extraction yield of 2.28% with a diffusivity value of 3.85 × 10-9 m2 s-1, which was higher than aqueous extraction method using a kinetic model based on Fick's second law of diffusion. The extracted polysaccharide showed no toxicity as measured through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assay on RAW cell line. Additionally, the polysaccharide over its critical micelle concentration (400, 500, 600 and 700 µg mL-1) offered emulsifying properties with 0.5%, 1% and 5% oil (v/v). The emulsion with a polysaccharide concentration of 600 µg mL-1 with 5% oil (v/v) provides stability against coalescence for 3 days. CONCLUSION: The overall findings indicated that UAE of AAM polysaccharide can be used for an efficient extraction method, and the obtained polysaccharide is nontoxic in nature and bears emulsifying properties. © 2024 Society of Chemical Industry.

Construction of arsenic selective chelating resin with iron precursor for removal of low-concentration arsenic: Breakthrough modeling and field deployment.

The presence of exorbitant arsenic contamination in the aquatic environment causes astronomically immense health quandaries affecting millions of people, which may lead to death in the case of prolonged indigestion of arsenic-containing drinking water. Herein, we are reporting porous chelating resin with an iron precursor for the removal of arsenic ions from water. Weak acid cation resin was functionalized under varying experimental conditions to get a suitable resin with high arsenic uptake. The theoretical results revealed that the maximum Langmuir adsorption capacities of 3.27 mg g-1 and 1.13 mg g-1 were achieved for As(V) and As(III), respectively. The kinetics of adsorption followed the pseudo-second-order (PSO) model with a high determination coefficient (R2) of 0.9963 and 0.9895 for As(V) and As(III), respectively. The Adams-Bohart, Thomas, Yoon-Nelson, and Pore diffusion models were used to identify the breakthrough curve in the fixed bed adsorption column. The column performance improved with a larger bed height (55 cm), low concentration of influent (0.25 mg L-1), and low flow rate of influent (80 mL min-1). Under this condition, the breakthrough time and exhaustion time were 314 min and 408 min for As(V) and 124 min and 185 min for As(III), respectively.

One-pot facile approach to design an efficient macro-porous polymeric matrix to remediate Hg(II)and Pb(II) from aqueous medium and its performance evaluation study by mathematical modelling.

In the present scenario discharge of heavy-metal ions into water bodies is a global threat that is causing serious health hazards even in low concentrations. Thus, in order to remediate the heavy-metal [Hg(II) and Pb(II)] toxicity, an organic-inorganic hybrid functional porous metallo-polymeric network i. e, poly(Zirconyl methacrylate-co-1-vinyl imidazole) (pZrVIm) was fabricated via one-pot facile synthesis approach. The pZrVIm architecture has shown high removal efficiency for Hg(II) and Pb(II) aqueous medium even in extremely low quantities. Advanced instrumental techniques were used to characterize the structural and morphological characteristics of pZrVIm. Different experimental variables i.e., reaction time, pH, initial feed concentration, co-ion effects etc. were explored to examine adsorption behaviour. The maximum adsorption capacities (qmax) of pZrVIm5 were calculated as 168.06 and 162.34 mg g-1 for Hg(II) and Pb(II) respectively by the Langmuir isotherm model. Data from isotherms showed that monolayer adsorption on a homogeneous surface is the rate-limiting stage and followed pseudo-second-order kinetic process. The Artificial Neural Network (ANN) modelling was used to validate kinetics and isotherm data which revealed high accuracy of the model with correlation coefficient values (R = 0.99). Various types of isotherm models such as Langmuir, Freundlich, Dubinin-Radushkevich, Temkin, Redlich-Peterson, Toth and Koble-Corigen have been studied to determine the adsorption phenomena. The pore diffusion model revealed breakthrough time of 91 h and 84 h, Hg(II) and Pb(II) with the feed concentration of 15 mg L-1 respectively. The study revealed that pZrVIm5 has great potential for heavy metal ions remediation for water treatment.

Effects of overlapping electric double layer on mass transport of a macro-solute across porous wall of a micro/nanochannel for power law fluid.

Effects of overlapping electric double layer and high wall potential on transport of a macrosolute for flow of a power law fluid through a microchannel with porous walls are studied in this work. The electric potential distribution is obtained by coupling the Poisson's equation without considering the Debye-Huckel approximation. The numerical solution shows that the center line potential can be 16% of wall potential at pH 8.5, at wall potential -73 mV and scaled Debye length 0.5. Transport phenomena involving mass transport of a neutral macrosolute is formulated by species advective equation. An analytical solution of Sherwood number is obtained for power law fluid. Effects of fluid rheology are studied in detail. Average Sherwood number is more for a pseudoplastic fluid compared to dilatant upto the ratio of Poiseuille to electroosmotic velocity of 5. Beyond that, the Sherwood number is independent of fluid rheology. Effects of fluid rheology and solute size on permeation flux and concentration of neutral solute are also quantified. More solute permeation occurs as the fluid changes from pseudoplastic to dilatant.

A socio-economic study along with impact assessment for laterite based technology demonstration for arsenic mitigation.

Arsenic contamination mitigation technologies have been adsorption-based, but the most widely-used and traditionally available adsorbents suffered inherent limitations, including cost infeasibility and problems associated with regeneration and disposal of the spent adsorbent. The present technology is based on indigenously developed activated laterite prepared from the naturally and abundantly available material, and can hence easily be scaled up for community usage and large scale implementation. The total arsenic removal capacity is 32.5mg/g, which is the highest among all naturally occurring arsenic adsorbents. A major issue in earlier adsorbents was that during regeneration, the adsorbed arsenic would be released back into the environment (leaching), and would eventually contaminate the groundwater again. But the adsorbent in this filter does not require regeneration during its five-year lifespan and does not leach upon disposal. An attempt is made to test and demonstrate the practical implementation of the technology - its effectiveness and viability in three community (primary schools - one in Malda and two in north 24 Parganas, West Bengal, India) and 20 household filters, catering to over 5000 people in different areas of West Bengal exposed to high arsenic contamination of groundwater (ranging from 0.05 to 0.5mg/l). The work also focuses on the social impact of the real life technological solution on the lives on the affected people in the worst hit arsenic affected communities, perhaps the greatest public health risk emergency of the decade.