Fixed bed and batch studies on biosorption of lead using Sargassum Tenerrimum powder: Characterization, Kinetics and Thermodynamics

Bioremediation of n-alkanes, polycyclic aromatic hydrocarbons, and heavy metals from wastewater using seaweeds

The removal of n-alkanes, polycyclic aromatic hydrocarbons, and heavy metals from wastewater using three dried seaweeds Ulva intestinalis Linnaeus (green alga), Sargassum latifolium (Turner) C.Agardh (brown alga), and Corallina officinalis Kützing (red alga) has been shown to evaluate their potential usage as inexpensive adsorbents. Under natural environmental conditions, numerous analytical methods, including zeta potential, energy dispersive X-ray spectroscopy (EDX), SEM, and FT-IR, are used in this study. The results showed that n-alkanes and polycyclic aromatic hydrocarbons adsorption increased with increasing contact time for all three selected algae, with a large removal observed after 15 days, while the optimal contact time for heavy metal removal was 3 h. S. latifolium dry biomass had more potential as bioadsorbent, followed by C. officinalis and then U. intestinalis. S. latifolium attained removal percentages of 65.14%, 72.50%, and 78.92% for light n-alkanes, heavy n-alkanes, and polycyclic aromatic hydrocarbons (PAHs), respectively, after 15 days. Furthermore, it achieved removal percentages of 94.14, 92.62, 89.54, 87.54, 82.76, 80.95, 77.78, 73.02, and 71.62% for Mg, Zn, Cu, Fe, Cr, Pb, Cd, Mn, and Ni, respectively, after 3 h. Carboxyl and hydroxyl from FTIR analysis took part in wastewater treatment. The zeta potentials revealed that algal cells have a negatively charged surface, and the cell surface of S. latifolium has a more negative surface charge than U. intestinalis and C. officinalis. Our study suggests that seaweeds could play an important role in wastewater treatment and thus help as an economical, effective, and ecofriendly bioremediation system for ecological health and life protection.

Bioadsorption of Fe (II) ions from aqueous solution using Sargassum latifolium aqueous extract and its synthesized silver nanoparticles

Algal extracts are used in the environmentally safe and economically advantageous biosynthesis of silver nanoparticles, which does not require the use of hazardous chemicals, high temperatures, pressures, or energies. In the current study, we created silver nanoparticles from the extract of the marine brown alga Sargassum latifolium, analyzed them with Transmission Electron Microscopy (TEM), FTIR, and UV-visible spectrophotometers, and used them to show how well they could remove Fe (II) ions from aqueous solutions. UV scan analyses of S. latifolium aqueous extract of silver nanoparticles showed a maximum peak at 450 nm. This peak is considered a characteristic peak for silver nanoparticles. Also, FTIR analysis of S. latifolium aqueous extract revealed various functional groups such as - OH, -NH, -CH, -COOH, CO, and C-C, which are responsible for bioadsorption of Fe (II). TEM also demonstrated that the synthesized nanoparticles were spherical, distinct, and regular, with particles size about 6.03-15.16 nm. S. latifolium aqueous extract silver nanoparticles were more effective than its aqueous extract in removing Fe (II) from an aqueous solution. The removal efficiency of Fe (II) by nanoparticles was 83%, while by the aqueous extract was 69%. The optimal conditions for bioadsorption of Fe (II) were pH 4, contact time 150, and adsorbent dose 0.01 g.

Use of COMSOL software for modeling and simulation of copper removal in a dynamic mode on a new biowaste

The main purpose of this investigation is to model the results related to biosorption using COMSOL (Multiphysics 4.3a), and to solve the advection-dispersion equation by using both linear and Langmuir models. A bidimensional model was then proposed to study the mass transfer in the process of copper ions sorption in a dynamic mode on cider vinegar residues. Sorption tests were realized by evaluating the influence of flow rate (0.75, 1, and 2.65 ml min^-1 ), bed height (3.5, 7 and 8.5 cm), and copper initial concentration (169 and 300 mg L^-1 ). For all cases, the mathematical formulation was solved by assuming that the column is homogeneous and the sorption is instantaneous. The corresponding results were exploited through breakthrough curve profiles, where it was shown that the solutions obtained by the "Langmuir COMSOL" model coincide with the experimental values. In contrast, the linear model has been unable to fit them. The optimal results were analyzed by Thomas, Adam-Bohart Yoon Nelson, and Ogata-Bank models, which proves that the Thomas method is well adapted with a satisfactory correlation coefficient (0.93). Further, the model validation was performed by determining the residual root mean square error, which was found less than 0.3, thereby indicating a reasonable concordance between the estimated and experimental points. The high sorption capacity obtained was around of 41.37 mg g^-1 , which suggests that the cider vinegar residues can be exploited as a low-cost, available, and effective sorbent biomass in the field of the treatment of industrial effluents. PRACTITIONER POINTS: Cider vinegar residues (CVR) as low cost biosorbent were studied for continuous biosorption. A successful COMSOL model was proposed and validated. CVR is an effective biosorbent for copper fixed bed biosorption. High sorption capacity was around of 41.37 mg g^-1 under optimal conditions.

A Prospective Study of the Exploitation of Pelagic Sargassum spp. as a Solid Biofuel Energy Source

This study presents a prospective study for the potential exploitation of pelagic Sargassum spp. as a solid biofuel energy source. It was carried out in three stages. First we conducted a morphological, physical-chemical, and structural characterization using scanning electron microscopy (SEM), infrared spectroscopy (FTIR), and X-ray diffraction (DRX), respectively. Second we evaluated the material’s functional properties as a solid biofuel based on its calorific value and the quantification of polymeric components like hemicellulose, cellulose, and lignin, as well as thermogravimetric and differential analysis to study the kinetics of its pyrolysis and determine parameters like activation energy (Ea), reaction order (n), and the pre-exponential factor (Z). Third we analyzed the energetic potential considering the estimated volume of pelagic Sargassum spp. that was removed from beaches along the Mexican Caribbean coast in recent years. Results of the kinetic study indicate that Sargassum spp. has an enormous potential for use as a complement to other bioenergy sources. Other results show the high potential for exploiting these algae as an energy source due to the huge volumes that have inundated Caribbean, West African, and northern Brazil shorelines in recent years. As a solid biofuel, Sargassum spp. has a potential energy the order of 0.203 gigajoules (GJ)/m3. In the energy matrix of the residential sector in Mexico, its potential use as an energy source is comparable to the national consumption of firewood. The volume of beachcast Sargassum spp. that was removed from ~8 km of coastline around Puerto Morelos, Mexico in 2018–2019, could have generated over 40 terajoules/year of solid biofuel.

Adsorption of Lead on Lentil Husk in Fixed Bed Column Bioreactor

This study depicts successful employment of fixed bed column bioreactor for adsorption of lead in continuous mode using lentil husk as sorbent. Design parameters considerably controlled the reactor performance, amongst which height of the fixed bed and flow rate were crucial in generating cleaner effluent. Adsorption capacity was found to shoot up to the level of 205.87 mg g^-1 at 10 cm bed height, 100 mg L^-1 feed concentration and 20 mL min^-1 flow rate. Kinetic study done at regular intervals of time revealed high percentage removal of lead (99-96%) throughout entire span of reactor operation. Experimental data were well interpreted by Thomas model and Yoon-Nelson model. The reactor bed was regenerated after each adsorption and loaded metal was recovered up to the extent of ∼96%. The column reactor was efficient enough to treat lead containing actual industrial effluents.