Effects of tissue nitrogen and media nitrate on trace metal uptake and trophic transfer by \u3cem\u3eUlva\u3c/em\u3e spp.

A general survey of trace metal content in Ulva spp. (Linnaeus) around Moss Landing, California was carried out. The next objective was to evaluate whether tissue nitrogen or media nitrate affects metal uptake (As, Pb, Mn, Zn) by Ulva spp. under eutrophic conditions. Additionally, the role of metal burden in the invertebrate Idotea resecata as a function of metal content in its diet was examined. Mean trace metal concentrations in Ulva differed significantly among sites in Moss Landing, California. Laboratory measurements using samples from 15 sites along the central California coast revealed a significant positive correlation between Ulva spp. tissue nitrogen and both arsenic and manganese uptake. No relationship was found between tissue nitrogen and lead or zinc, but a significant positive correlation with the relative change in manganese and lead was observed. Though statistically insignificant, a regression analysis revealed a logarithmic relationship between media nitrate and both tissue arsenic and manganese. Lead and zinc content in Ulva had no relationship with media nitrate. Metal in Idotea resecata was not significantly related to diet treatments; however, a bioaccumulation trend was observed for arsenic and manganese. Given the role of trace metals in the production of photosynthetic enzymes and proteins, variability in productivity may drive the uptake of essential and non-essential elements. Depending on the amount of Ulva consumed, elevated metal content in these macroalgae could pose a health risk to invertebrates and/or humans

Effects of Tissue Nitrogen and Media Nitrate on Trace Metal Uptake and Trophic Transfer by Ulva spp.

A general survey of trace metal content in Ulva spp. (Linnaeus) around Moss Landing, California was carried out. The next objective was to evaluate whether tissue nitrogen or media nitrate affects metal uptake (As, Pb, Mn, Zn) by Ulva spp. under eutrophic conditions. Additionally, the role of metal burden in the invertebrate Idotea resecata as a function of metal content in its diet was examined. Mean trace metal concentrations in Ulva differed significantly among sites in Moss Landing, California. Laboratory measurements using samples from 15 sites along the central California coast revealed a significant positive correlation between Ulva spp. tissue nitrogen and both arsenic and manganese uptake. No relationship was found between tissue nitrogen and lead or zinc, but a significant positive correlation with the relative change in manganese and lead was observed. Though statistically insignificant, a regression analysis revealed a logarithmic relationship between media nitrate and both tissue arsenic and manganese. Lead and zinc content in Ulva had no relationship with media nitrate. Metal in Idotea resecata was not significantly related to diet treatments; however, a bioaccumulation trend was observed for arsenic and manganese. Given the role of trace metals in the production of photosynthetic enzymes and proteins, variability in productivity may drive the uptake of essential and non-essential elements. Depending on the amount of Ulva consumed, elevated metal content in these macroalgae could pose a health risk to invertebrates and/or humans

Effects of Tissue Nitrogen and Media Nitrate on Trace Metal Uptake and Trophic Transfer by Ulva spp.

A general survey of trace metal content in Ulva spp. (Linnaeus) around Moss Landing, California was carried out. The next objective was to evaluate whether tissue nitrogen or media nitrate affects metal uptake (As, Pb, Mn, Zn) by Ulva spp. under eutrophic conditions. Additionally, the role of metal burden in the invertebrate Idotea resecata as a function of metal content in its diet was examined. Mean trace metal concentrations in Ulva differed significantly among sites in Moss Landing, California. Laboratory measurements using samples from 15 sites along the central California coast revealed a significant positive correlation between Ulva spp. tissue nitrogen and both arsenic and manganese uptake. No relationship was found between tissue nitrogen and lead or zinc, but a significant positive correlation with the relative change in manganese and lead was observed. Though statistically insignificant, a regression analysis revealed a logarithmic relationship between media nitrate and both tissue arsenic and manganese. Lead and zinc content in Ulva had no relationship with media nitrate. Metal in Idotea resecata was not significantly related to diet treatments; however, a bioaccumulation trend was observed for arsenic and manganese. Given the role of trace metals in the production of photosynthetic enzymes and proteins, variability in productivity may drive the uptake of essential and non-essential elements. Depending on the amount of Ulva consumed, elevated metal content in these macroalgae could pose a health risk to invertebrates and/or humans

Development of sodium alginate@ZnFe-LDHs functionalized beads: Adsorption properties and mechanistic behaviour of phosphate and nitrate ions from the aqueous environment

Phosphate and nitrate are the vital micro-nutrients and a substantial contributor to the growth of biomass, energy storage, and agricultural activities. However, in their increased concentrations, they also cause potential health problems to human and all other living beings. Layered double hydroxides (LDHs) are highly selective and efficient material for the remediation of the ions of phosphate and nitrate from water, but agglomerate easily due to their high surface properties and are difficult to recover from aqueous solutions. The preparation of LDHs functionalized beads of the biopolymeric background is an alternative to overcome these difficulties. Herein, the present work examined the adsorptive removal of the above-mentioned toxic ions from water using ZnFe-LDHs assembled alginate (ZnFe-LDHs@Alg) beads. The removal efficiency and percentage were examined along with various influencing factors like sorbent dosage, solution pH, contact time, and co-ions also carried out. ZnFe-LDHs@Alg beads revealed an extreme removal efficiency of 94.64 and 74.12 mg/g for the ions of phosphate and nitrate, respectively. The phosphate and nitrate removal by ZnFe-LDHs@Alg beads showed reliability with the Freundlich isotherms. The above findings suggested that ZnFe-LDHs@Alg beads can be used as an efficient and selective sorbent for the remediation of toxic ions from water/ wastewater

Fabrication of La³⁺ Impregnated Chitosan/β-Cyclodextrin Biopolymeric Materials for Effective Utilization of Chromate and Fluoride Adsorption in Single Systems

Lanthanum impregnated chitosan/β-cyclodextrin (CS–La−βCD) composite was prepared using a facile <i>in situ</i> fabrication method and successfully evaluated for the adsorption of CrO₄^2– and F^–. The pristine and treated CS–La−βCD was characterized using Fourier transform infrared, scanning electron microscopy, energy dispersive X-ray spectroscopy with mapping, X-ray diffraction, and thermal gravametric analytical techniques. The optimum conditions for the uptake of CrO₄^2– and F^– were investigated as a function of shaking time, dosage, initial ion concentration, pH, and predatory ions in batch experiments. The equilibrium data were fitted using Langmuir, Freundlich, and Dubinin–Radushkevich models for the defluoridation and sorption of chromium onto CS–La−βCD. The adsorption kinetics of CrO₄^2– and F^– followed the pseudo-second order model. The maximum Langmuir adsorption capacity was found to be 91.58 mg/g and 8.14 mg/g for CrO₄^2– and F^–, respectively at 303 K. Sequential adsorption and desorption studies were carried out up to five cycles using 0.1 M of NaOH as an eluent to check the reusability of the adsorbents

Synthesis and characterization of Ce(III) decorated Duolite resin and its removal performance of toxic anions from aqueous solutions

Nitrate and phosphate are major threats for water/ wastewater which grounds eutrophication's and methemoglobinemia diseases, respectively and also severely hazards the safety of aquatic beings and public health's. To deal with the purging of aqueous nitrate and phosphate contamination, a low-cost Ce(III) decorated Duolite A 368 Plus resins (Ce-DA) were used. The influence of various adsorption factors was studied, such as adsorbent dosage, shaking time, pH, initial concentrations of nitrate and phosphate ions, competitive co-ions, isotherms and kinetic studies at different experimental temperatures etc. Ce-DA resin formed complexation with target nitrate and phosphate ions by adsorption via ion exchange and electrostatic attractions. Results from nitrate and phosphate adsorption showed that Ce-DA was greatly pH adjustable with an optimum pH of 3 to 7. The kinetic study revealed the pseudo-second-order and the Langmuir isotherm assessed a maximum adsorption efficiency of 138.67 and 156.26 mg/g for nitrate and phosphate ions respectively, which was higher than unloaded DA resin. The adsorption-desorption operations, demonstrating a great recovering performance of the adsorbent upto five successive cycles. This work highlights the cost-effective method to prepare promising adsorbent for efficient removal of toxic ions nitrate and phosphate from water

Synergistic Effect of Chitosan and Titanium Dioxide on the Removal of Toxic Dyes by the Photodegradation Technique

The photodegradation of three different types of dyes like an anionic dye, a cationic dye, and a zwitterionic dye, namely, Reactive Red 2 (RR), Methylene Blue (MB), and Rhodamine B (RB), respectively, have been carried out using chitosan/TiO₂ composite (CTC). The as-synthesized CTC was characterized by Fourier transform infrared (FTIR) spectral studies, scanning electron microscopy (SEM), energy dispersive analysis of X-ray (EDAX), BET, X-ray diffraction (XRD), and thermal analysis (thermogravimetric analysis (TGA) and differential thermal analysis (DTA)). The enhanced photocatalytic activity of CTC for the degradation of the dyes was attributed to the synergistic effect of TiO₂ and chitosan (CS). The photodegradation experiments were carried out by varying different parameters such as irradiation time, dosage, pH, initial dye concentration, coexisting ions, hydrogen peroxide, and light intensity. The kinetic behavior was described in terms of the Langmuir–Hinshelwood model. The confirmation of mineralization of dyes has been studied by measuring chemical oxygen demand (COD)

Synthesis and Characterization of a Few Amino-Functionalized Copolymeric Resins and Their Environmental Applications

The synthetic copolymeric resins acrylonitrile/divinylbenzene/vinylbenzyl chloride (AN/DVB/VBC), styrene/divinylbenzene/vinylbenzyl chloride (ST/DVB/VBC), and vinylbenzyl chloride/divinylbenzene (VBC/DVB) have been prepared by suspension polymerization. These polymeric matrixes were aminated with ethylenediamine (ED) and then protonated to increase their selectivity toward Cr­(VI). The experiments were carried out in batch mode to optimize various influencing parameters, namely, contact time, pH, other interfering co-ions, and temperature. The chromium removal capacity (CRC) of AN/DVB/VBC–ED resin was found to be higher than those of the other prepared copolymers. The mechanism of chromium removal was governed by electrostatic-adsorption-coupled reduction and complexation. The polymeric resins and chromium-sorbed resins were characterized by FTIR, SEM–EDAX, BET, elemental analysis, and EPR studies. The adsorption data were fitted with Freundlich and Langmuir isotherms. The calculated values of thermodynamic parameters indicated the nature of chromium sorption