Synthesis and application of alginate-nanocellulose composite beads for defluoridation process in a batch and fluidized bed reactor

Highly efficient mesoporous aluminium-magnetite-alginate magnetic composite for defluoridation of water

One of the few elements that can have negative health impacts in both conditions, when consumed in excess or insufficiency is fluoride. In current study, aluminium magnetite alginate composite (AMA) was fabricated and applied using batch adsorption of fluoride as well as by using statistical modelling. Heterogeneous surface as revealed from scanning electron micrograph, thermal stability shown by thermal studies, high surface area of 29.77 m2 g-1, pore volume 0.1987 cm3 g-1 with mesoporous structure having average pore radius of 133 Å shown by BET analysis, fare degree of magnetization from VSM analysis were the important features of this material. Screening experiments and batch trials were carried out to obtain optimum working conditions. pH of 3.0, dosage of 50 mg, interaction period of 60 min and concentration of 50 mg L-1 depicted maximum defluoridation efficacy of about 94%. The adsorption capacity was found to be 60.08 mg g-1 in accordance with Langmuir adsorption isotherm, while pseudo second order kinetics was followed. Overall effects of various factors on sorption process were optimized using response surface methodology (RSM). Regeneration potential of AMA has been demonstrated for 10 adsorption-desorption cycles, showing more than 60% efficiency in tenth cycle. The AMA composite shows E-factor value 0.004 depicting it is sustainable in environment. In short, this novel composite showed excellent morphological, magnetic, functional properties that led to enhanced adsorption efficiency in short span of time that can be regenerated and reused in multiple cycles.

Nanocellulose-alginate composite beads for improving Ciprofloxacin bioavailability

Nanocellulose is a potential material utilized in numerous biomedical applications. However, its hydrophilic characteristic and uncontrolled encapsulated drug release hinders nanocellulose uses in oral drug administration. Thus, this work developed novel nanocellulose/alginate composite (CNC/Alg) beads for oral delivery and bioavailability enhancement of a model drug, Ciprofloxacin (CIP). CNC was green synthesized employing electrolysis process from sugarcane bagasse. CNC/Alg beads were formulated by dropwise adding CNC-Alg mixture in CaCl2 solution at room temperature. CIP was incorporated into CNC/Alg beads by adsorption technique. X-ray diffractometry and Fourier-transform infrared spectra images showed that the beads were effectively produced with high crystallinity of 75.5 %, and the typical bond of cellulose and alginate. Within 4 h of adsorption, CIP loading efficiency reached 45.27 %, with 87.2 % molecules in the zwitterionic state. The adsorption followed Elovich and pseudo-second-order models, indicating a multi-mechanism including both physical and chemical adsorptions. Importantly, in gastrointestinal tract, the beads could protect CIP from acidic stomach environment while releasing it sustainably in simulated intestinal condition (75.05 %). The beads also showed strong antibacterial activity against both Gram(-) and Gram(+) bacteria, as evidenced by low IC50 and minimum inhibitory concentration values. Finally, CNC/Alg beads could improve CIP bioavailability for effective oral drug delivery route.

Enhancing catalyst stability: Immobilization of Cu-Fe catalyst in sodium alginate matrix for methyl orange removal via Fenton-like reaction

This study aims to enhance the stability and effectiveness of heterogeneous catalysts in Fenton-like reactions, explicitly addressing the acidity limitations inherent in traditional Fenton processes. Copper-iron was synthesized through co-precipitation, and a catalyst bead was produced from hydrogel formation. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) confirm phases in the bimetallic Copper-iron, aligning with the intended composition. Modification with alginate led to reduced metal leaching compared to the bare bimetallic counterpart, as confirmed by atomic absorption spectroscopy (AAS). Additionally, Fourier-transform infrared spectroscopy (FTIR) revealed the deactivation of alginate through the disappearance of carboxyl groups, indicating the depolymerization of the catalyst bead. Under the suggested conditions (Methyl Orange concentration of 25 mg/L, initial solution pH of 7, 2 g/L catalyst loading, concentration of hydrogen peroxide 100 mM in a 120-min reaction time), the catalyst demonstrated remarkable decolorization efficiency of Methyl Orange, achieving 97.67 %. Further highlighting its practicality, the catalyst exhibited outstanding reusability over four cycles under identical conditions, showcasing robust immobilization capabilities and sustained performance. Notably, the catalyst's magnetic properties facilitated easy separation using an external magnet. In conclusion, the developed catalyst beads offer a solution with high reusability, magnetic separability, and reduced iron leaching. The advantageous characteristics underscore its potential as a heterogeneous catalyst for wastewater treatment applications, warranting further exploration under practical conditions.

Advances and future perspectives of water defluoridation by adsorption technology: A review

Fluoride contamination in water sources poses a significant challenge to human health and the environment. In recent years, adsorption technology has emerged as a promising approach for water defluoridation due to its efficiency and cost-effectiveness. This review article comprehensively explores the advances in water defluoridation through adsorption processes. Various adsorbents, including natural and synthetic materials, have been investigated for their efficacy in removing fluoride ions from water. The mechanisms underlying adsorption interactions are elucidated, shedding light on the factors influencing defluoridation efficiency. Moreover, the review outlines the current state of technology, highlighting successful case studies and field applications. Future perspectives in the field of water defluoridation by adsorption are discussed, emphasizing the need for sustainable and scalable solutions. The integration of novel materials, process optimization, and the development of hybrid technologies are proposed as pathways to address existing challenges and enhance the overall efficacy of water defluoridation. This comprehensive assessment of the advances and future directions in adsorption-based water defluoridation provides valuable insights for researchers, policymakers, and practitioners working towards ensuring safe and accessible drinking water for all.

Saccharomyces pastorianus Residual Biomass Immobilized in a Polymer Matrix as a Biosorbent for Reactive Dye Removal: Investigations in a Dynamic System

The use of residual microbial biomass from various industries in emerging pollutant removal strategies represents a new area of research in the field. In this case, we examined how to remove reactive dyes from an aqueous solution utilizing a biosorbent made of residual biomass from immobilized Saccharomyces pastorianus (S. pastorianus) in a polymer matrix using a dynamic system. Fluidized bed column biosorption investigations were carried out on a laboratory scale. Brilliant Red HE-3B was chosen as the target molecule. The main parameters considered for this purpose were the flow rate (4.0 mL/min; 6.1 mL/min), initial pollutant concentration (51.2 mg/L; 77.84 mg/L), and biosorbent mass (16 g; 20 g). The experimental data of the fluidized bed study were evaluated by mathematical modeling. The Yoon-Nelson, Bohart-Adams, Clark, and Yan models were investigated for an appropriate correlation with the experimental data. An acceptable fit was obtained for a flow rate of 4 mL/min, an initial pollutant concentration of 51.2 mg/L, and a biosorbent amount of 20 g. The obtained results indicate that the biosorbent can be used efficiently in a dynamic system both for the removal of the studied dye and in extended operations with a continuous flow of wastewater. As a conclusion, the investigated biocomposite material can be considered a viable biosorbent for testing in the removal of reactive dyes from aqueous environments and creates the necessary conditions for the extension of studies toward the application of these types of biosorbents in the treatment of industrial effluents loaded with organic dyes.

Adsorptive exclusion of crystal violet dye using barium encapsulated alginate/carbon composites: characterization and adsorption modeling studies

The present study is devoted to the removal of crystal violet dye using the synthesized barium alginate/carbon composites abbreviated as BA (barium alginate), BAAC (barium alginate/activated carbon), BASC (barium alginate/starch carbon), and BASSC (barium alginate/starch carbon modified with CTAB). The adsorptive removal of crystal violet as a function of contact time, pH of solution, composite dose, initial dye concentration, and temperature was studied. The uptake of crystal violet (CV) dye for the composites was recorded in the range of 36 mg g-1 to 50 mg g-1 at pH 8.03 ± 0.03 for an equilibrium time of 120 min. The adsorption kinetics and isotherms in compliance with the CV sorption onto BA/carbon composites corroborated the utmost fit of pseudo-second-order and Freundlich isotherm models, respectively. The recycling process was achieved using the barium alginate-treated bead carbons for different initial CV dye concentrations of 10-30 mg L-1 with a scope of zero disposal. The practicability of BA/carbon composites in a groundwater sample spiked with 30 mg L-1 of CV was successfully achieved with a removal efficiency of about 65-74%. Characterization studies for the composites using FTIR, SEM (with EDS), XRD, TGA, and BET were carried out and discussed in the paper.