Mg-Al Mixed Oxide Adsorbent Synthesized Using FCT Template for Fluoride Removal from Drinking Water

Adsorption removal of fluoride from polluted drinking waters using Mn-Al-La oxide

Trimetal oxides have received high attention in treatment of fluoride-polluted drinking waters. In this study, Mn-Al-La (MAL) oxide with a mole ratio of 2:1:1 was successively prepared and characterized by XRD, FTIR, XPS, and TEM. It exhibited as cotton-like assemblages (500-800 nm of axial lengths), and BET specific surface area was 52 m2/g. It was used to study fluoride adsorptions in aqueous solutions by batch experiments, under different adsorbent/adsorbate levels, times, temperatures, pH and coexisting anions, and treat simulated groundwater (with 2.85 mg/L fluoride and pH 7.0) by batch and column tests. Adsorption data well fitted to pseudo-second-order rate model (R2 = 0.996-0.999), and Langmuir (R2 = 0.962 - 0.997) and Freundlich (R2 = 0.964-0.989) isothermal models. Their maximum adsorption capacities could reach 45-113 mg/g. Only H2PO4- anions had a restrictive impact at pH 7.0, and there was a good removal ability at pH 3-9. Adsorption processes were spontaneous, endothermic, and random. Adsorption mechanisms were electrostatic interaction and ligand exchange at pH 7.0. Adsorption capacity could reach 73% of initial value at pH 7.0, after three cycles. All application data on the polluted groundwater treatments show MAL oxide is a potential adsorbent for fluoride removals.

Preparation of alumina-supported Fe-Al-La composite for fluoride removal from an aqueous matrix

Using groundwater for human consumption is an alternative for places with no nearby surface water resources. Fluoride is commonly found in groundwater, and the consumption of this water for a prolonged time in concentrations that exceed established limits by WHO and Brazilian legislation on water potability (1.5 mg L^-1) can cause harmful problems to human health. For this reason, fluoride removal is an important step before water consumption. In this work, activated alumina was impregnated with Fe-Al-La composite and employed for the first time as an adsorbent for fluoride removal from an aqueous environment. XRD, SEM/EDS, FT-IR, and point of zero charge were used to characterize the prepared adsorbent. The adsorptive performance of adsorbent material was investigated by employing a 2³-central composite design (CCD), and the obtained experimental conditions were pH = 6.5 and adsorbent dosage = 3.0 g L^-1. A maximum adsorption capacity of 8.17 mg g^-1 at 298 K and pH = 6.5 was achieved by Langmuir isotherm to describe the adsorption. The kinetic model that better described experimental data was Avrami, with the k_av parameter increasing with the initial concentration from 0.076 to 0.231 (min^-1)ⁿ_av. The nature of adsorption was found to be homogeneous, and it occurs in a monolayer. The fluoride removal performance for the prepared adsorbent was higher than granular activated alumina, showing that supporting Fe-Al-La at the alumina surface increased its fluoride adsorption capacity from 16 to 42% at the same experimental conditions. Finally, the influence of co-existing ions Cl^-, SO₄^2-, and NO₃^- was evaluated in fluoride adsorption, and the material presented great selectivity to fluoride. Thus, Fe-Al-La/AA adsorbent is a promising material for fluoride removal from water.

Fluoride ions sorption using functionalized magnetic metal oxides nanocomposites: a review

Fluoride is an anionic pollutant found superfluous in surface or groundwater as a result of anthropogenic actions from improper disposal of industrial effluents. In drinking water, superfluous fluoride has been revealed to trigger severe health problems in humans. Hence, developing a comprehensive wastewater decontamination process for the effective management and preservation of water contaminated with fluoride is desirable, as clean water demand is anticipated to intensify considerably over the upcoming years. In this regard, there have been increased efforts by researchers to create novel magnetic metal oxide nanocomposites which are functionalized for the remediation of wastewater owing to their biocompatibility, cost-effectiveness, relative ease to recover and reuse, non-noxiousness, and ease to separate from solutions using a magnetic field. This review makes an all-inclusive effort to assess the effects of experimental factors on the sorption of fluoride employing magnetic metal oxide nanosorbents. The removal efficiency of fluoride ions onto magnetic metal oxides nanocomposites were largely influenced by the solution pH and ions co-existing with fluoride. Overall, it was noticed from the reviewed researches that the maximum sorption capacity using various metal oxides for fluoride sorption was in the order of aluminium oxides >cerium oxides > iron oxides > magnesium oxides> titanium oxides, and most sorption of fluoride ions was inhibited by the existence of phosphate trailed by sulphate. The mechanism of fluoride sorption onto various sorbents was due to ion exchange, electrostatic attraction, and complexation mechanism.

Food’s Waste Water Biosolid Assessment against Toxic Element Absorbability of Food’s Cropping Soil Plant by Dominance Theory

The blending of the Food’s Waste Water Biosolid (FWWB) fertilizer with Food’s Cropping Soil (FsCS) results the absorption of the toxic macromicroorganisms from FsCS (is known as absorbability index). It is observed that such as blending not only increase the fertility and productivity of FsCS by neutralizing or absorbing the macromicroorganisms but also catering the necessary nutrition to plants. The authors sensed that a few research works are conducted recently in the dimension of evaluating the best FWWB among available FWWBs under $O$ -(objective) FWWB’s parameter models. On potential analysis of published research works, the authors claimed that there is yet no research document, which can evaluate the best FWWB among available FWWBs or assess the best absorbability index of $O$ -(objective) as well as $S$ -(subjective) FWWB’s model corresponding to evaluated FWWBs or alternative points. It is accepted as a first research challenge. On extensive review, the authors determined that published FWWB’s parameter models are simulated by only single or nondynamic multivariable optimization techniques, which is accepted as a second research challenge. To address both research challenges, preliminary, the authors developed and proposed FWWB’s parameter model, consisted of physical, chemical, and biological parameters corresponding to $O$ and $S$ in nature via auditing a real case of FWWB alternative points such as Narendr Rice Mill- $P^1$ , Liese Mahamaya Rice Mill- $P^2$ , Vijay Rice Mill- $P^3$ , Mahim Rice Mill- $P^4$ , and Dhansingh Rice Mill- $P^5$ and their characteristics vs. parameters. Next, the authors framed the FWWB parameter model by acquiring $O$ and $S$ information against $O$ -physical, chemical, and $S$ -biological parameters corresponding to FWWB alternative points. To evaluate the results, the authors applied the robust multiparameter optimization “RMPO” (crisp VIKOR “VIseKriterijumska Optimizacija I Kompromisno Resenje” and FMF “Full Multiplicative Form technique with dominance theory”) approach on defuzzified $S$ -data and $O$ -data to evaluate the best FWWB point among available based on absorbability index assessment. The results are described in summary part.

Kinetic and Thermodynamic Characteristics of Fluoride Ions Adsorption from Solution onto the Aluminum Oxide Nanolayer of a Bacterial Cellulose-Based Composite Material

The described research examined the adsorption of fluoride ions from solution immobilized onto an aluminum oxide-coated bacterial cellulose-based composite material in which aluminum oxide had been deposited using ALD technology. The kinetic regularities of the adsorption of fluoride ions from the solution as well as the mechanism of the processes were analyzed. The established equations show that the dynamics of adsorption correspond to first-order kinetics. Based on the Langmuir adsorption isotherms, we defined the adsorption equilibrium constants, parameter maximum adsorption, and change in Gibbs free energy. It is shown that, with increasing temperature, an increase in the reaction rate is constant, both forward and reverse. This testifies to the activated character of adsorption of the first fluoride on the surface of the sorbent based on bacterial cellulose modified with an alumina nanolayer. The activation energy of the desorption process is higher than the activation energy of the adsorption process, which characterizes the adsorption as ionic. The negative value of entropy indicates that in the course of sorption, an adsorption complex "aluminum-fluorine" is formed, where the system is more ordered than the initial system in which fluorine ions are in solution. The limiting stages of the process are revealed. The high sorption capacity of the resulting bacterial cellulose-based composite material obtained by means of biosynthesis through cultivation of the bacterium Komagataeibacter sucrofermentans B-11267 was demonstrated.

Investigation of kinetics and adsorption isotherm for fluoride removal from aqueous solutions using mesoporous cerium-aluminum binary oxide nanomaterials

Herein, we report the synthesis of Ce–Al (1 : 1, 1 : 3, 1 : 6, and 1 : 9) binary oxide nanoparticles by a simple co-precipitation method at room temperature to be applied for defluoridation of an aqueous solution. The characterization of the synthesized nanomaterial was performed by XRD (X-ray diffraction), FTIR (Fourier transform infrared) spectroscopy, TGA/DTA (thermogravimetric analysis/differential thermal analysis), BET (Brunauer–Emmett–Teller) surface analysis, and SEM (scanning electron microscopy). Ce–Al binary oxides in 1 : 6 molar concentration were found to have the highest surface area of 110.32 m² g⁻¹ with an average crystallite size of 4.7 nm, which showed excellent defluoridation capacity. The adsorptive capacity of the prepared material towards fluoride removal was investigated under a range of experimental conditions such as dosage of adsorbents, pH, and initial fluoride concentration along with adsorption isotherms and adsorption kinetics. The results indicated that fluoride adsorption on cerium–aluminum binary metal oxide nanoparticles occurred within one hour, with maximum adsorption occurring at pH 2.4. The experimental data obtained were studied using Langmuir, Freundlich, and Temkin adsorption isotherm models. The nanomaterial showed an exceptionally high adsorbent capacity of 384.6 mg g⁻¹. Time-dependent kinetic studies were carried out to establish the mechanism of the adsorption process by pseudo-first-order kinetics, pseudo-second-order kinetics, and Weber–Morris intraparticle diffusion kinetic models. The results indicated that adsorption processes followed pseudo-second-order kinetics. This study suggests that cerium–aluminum binary oxide nanoparticles have good potential for fluoride removal from highly contaminated aqueous solutions.

Mesoporous Ce–Al binary oxide nanomaterials prepared with a surface area of 110.32 m² g⁻¹ showed defluoridation capacity at pH 2.4, exhibited maximum adsorption capacity of 384.6 mg g⁻¹ and a removal efficiency of 91.5% at a small dose of nanoadsorbent.

Characterizing Bacterial Cellulose Produced byKomagataeibacter sucrofermentans H-110 on Molasses Medium and Obtaining a Biocomposite Based on It for the Adsorption of Fluoride

Currently, there is an increased demand for biodegradable materials in society due to growing environmental problems. Special attention is paid to bacterial cellulose, which, due to its unique properties, has great prospects for obtaining functional materials for a wide range of applications, including adsorbents. In this regard, the aim of this study was to obtain a biocomposite material with adsorption properties in relation to fluoride ions based on bacterial cellulose using a highly productive strain of Komagataeibacter sucrofermentans H-110 on molasses medium. Films of bacterial cellulose were obtained. Their structure and properties were investigated by FTIR spectroscopy, NMR, atomic force microscopy, scanning electron microscopy, and X-ray structural analysis. The results show that the fiber thickness of the bacterial cellulose formed by the K. sucrofermentans H-110 strain on molasses medium was 60–90 nm. The degree of crystallinity of bacterial cellulose formed on the medium was higher than on standard Hestrin and Schramm medium and amounted to 83.02%. A new biocomposite material was obtained based on bacterial cellulose chemically immobilized on its surface using atomic-layer deposition of nanosized aluminum oxide films. The composite material has high sorption ability to remove fluoride ions from an aqueous medium. The maximum adsorption capacity of the composite is 80.1 mg/g (F/composite). The obtained composite material has the highest adsorption capacity of fluoride from water in comparison with other sorbents. The results prove the potential of bacterial cellulose-based biocomposites as highly effective sorbents for fluoride.

Determination of Physicochemical Parameters and Levels of Heavy Metals in Food Waste Water with Environmental Effects

Bioinorganic chemistry is found as a sizzling field in today's era. It deals with chemistry amongst the heavy metals with natural resources, i.e., air, soil, water, plant byproducts (foods), and environmental essences. The aim of this research is to determine the concentration of heavy metals present in the food waste water sample and to study the environmental effects of metal ion concentration. To conduct the research work, the physicochemical parameters and levels of five heavy metals of food waste water samples were collected from five sampling points of renowned hotels, restaurants, canteens, and confectionaries of a state of India and assessed using the standard analytical procedure. Sampling was carried out from January 2017 up to December 2017. The physicochemical parameters were determined such as pH, temperature, turbidity, conductivity, total dissolved solids, total suspended solids, total alkalinity, biological oxygen demand, chemical oxygen demand, dissolved oxygen, total organic carbon, sulphate, nitrate, and phosphate. The heavy metal concentration was determined by using the UV-spectrophotometer, and the results were compared with the standards prescribed by the WHO, BIS, ICMR, and municipal authorities. The results obtained in the physicochemical analysis revealed that a few parameters were found beyond limits, and the metal ion concentration (iron and zinc) results were found above the permissible limits set by the CPCB (Central Pollution Control Board), ICMR, BIS, and World Health Organization (WHO), most especially, effluent from point P1. It was concluded that all the effluents required further treatment before releasing them into the water body or land to prevent pollution. The obtained results reveal that waste water used for irrigation and farming of nearby areas and water drained from restaurant kitchens were considerably polluted and not suitable for aquatic organisms, irrigation, and agricultural purposes.