Removal Efficiency Of Pb Research Articles

Effects of biochar layer position on treatment performance and microbial community in subsurface flow constructed wetlands for removal of cadmium and lead

Levels of cadmium (Cd) and lead (Pb) correspond to common composition in acid mine wastewater of Hunan Province of China. The removal path of Cd and Pb and the structure of microbial community were investigated by developing constructed wetlands (CWs) with different layer positions of biochar. The biochar as a layer at the bottom of CW (BCW) system exhibited maximum Cd and Pb removal efficiencies of 96.6–98.6% and 97.2–98.9%, respectively. Compared with original soil, BCW increased the relative proportions of Proteobacteria, Firmicutes, Acidobacteriota, Verrucomicrobiota, Desulfobacterota, Armatimonadota, Bacteroidota, Patescibacteria, Basidiomycota (phylum level) and Burkholderia–Caballeronia–Paraburkholderia, Citrifermentans, Chthonomonadales, Cellulomonas, Geothrix, Terracidiphilus, Gallionellaceae, Microbacterium, Vanrija, Apiotrichum, Saitozyma, Fusarium (genus level). The concentrations of Cd and Pb were positively correlated with the abundance of Verrucomicrobiota, Basidiomycota (phylum level), and Methylacidiphilaceae, Meyerozyma, Vanrija (genus level). This study demonstrates that BCW system can improve removal performance toward Cd and Pb, as well as alter microbial community.

Pb Removal Efficiency by Calcium Carbonates: Biogenic versus Abiogenic Materials.

The sorption of heavy metals on mineral surfaces plays a key role in controlling the fate and bioavailability of harmful elements through dissolution-precipitation reactions. Here, we investigate the efficiency of Pb removal from highly contaminated waters by two calcium carbonate hard tissues, scallop shells (up to 99.9 mol %; -biocalcite) and cuttlefish bones (up to 90.0 mol %; bioaragonite), which template the precipitation of the highly insoluble mineral cerussite (PbCO3). The experiments show that both biomaterials are about five times more effective Pb scavengers (5 mmol of cerussite precipitated/g sample) than their inorganic counterparts (∼1 mmol/g). We relate this enhanced Pb scavenging capacity of biocarbonates to their composite organic-inorganic nature, which modulates their specific nano- and microstructural features and defines their larger surface areas, solubility, and reactivity compared to those of their inorganic counterparts. The oriented growth of cerussite progressively passivates the bioaragonite surface, reducing its long-term Pb scavenging capacity. In contrast, the randomly oriented growth of cerussite crystals on biocalcite prevents surface passivation and explains why biocalcite outperforms bioaragonite as a long-term Pb scavenger. The use of biocarbonates could be a key for designing more efficient decontamination strategies for heavy metal-polluted waters.

Immobilization mechanisms of heavy metals by utilizing natural cow bone waste for municipal solid waste incineration fly ash treatment.

Municipal solid waste incinerator (MSWI) fly ash poses intricate compositional challenges and potential environmental hazards. Effective management of such hazardous waste is imperative to mitigate the release of toxic compounds into the environment. Solidification/stabilization (S/S) processes have emerged as a viable strategy to transform MSWI fly ash from incineration waste into a safer and more environmentally benign material. This study aims to comprehensively investigate the potential of utilizing cow bone waste to stabilize heavy metals, focusing on Pb, within municipal solid waste incineration fly ash. Experimental investigations encompassed cow bone-to-fly ash weight ratios ranging from 0.0 (control group) to 7:3, a settling time of 2h, and a liquid-to-solid (L/S) ratio of 1.0mL/g. Cow bone waste exhibited pronounced efficacy, particularly within the short settling time, yielding a remarkable Pb removal efficiency of up to 99% at a cow bone waste dose of merely 2% and an L/S ratio of 1.0mL/g. Concurrently, other heavy metals such as Cd, Cu, and Zn were effectively stabilized with a cow bone waste dose of 1.5% during the same 2-h settling period. The results underscore the pivotal roles of ash/bone ratio and settling time in augmenting Pb stabilization in MSWI fly ash. The application of cow bone waste is anticipated to offer a cost-effective and environmentally sound approach, aligning with sustainable waste management principles.

Simultaneous immobilization of multiple heavy metal(loid)s in contaminated water and alkaline soil inoculated Fe/Mn oxidizing bacterium

Two strains of Fe/Mn oxidizing bacteria tolerant to high concentrations of multiple heavy metal(loid)s and efficient decontamination for them were screened. The surface of the bio-Fe/Mn oxides produced by the oxidation of Fe(II) and Mn(II) by Pseudomonas taiwanensis (marked as P4) and Pseudomonas plecoglossicida (marked as G1) contains rich reactive oxygen functional groups, which play critical roles in the removal efficiency and immobilization of heavy metal(loid)s in co-contamination system. The isolated strains P4 and G1 can grow well in the following environments: pH 5-9, NaCl 0-4%, and temperature 20-30°C. The removal efficiencies of Fe, Pb, As, Zn, Cd, Cu, and Mn are effective after inoculation of the strains P4 and G1 in the simulated water system (the initial concentrations of heavy metal(loid) were 1 mg/L), approximately reaching 96%, 92%, 85%, 67%, 70%, 54% and 15%, respectively. The exchangeable and carbonate bound As, Cd, Pb and Cu are more inclined to convert to the Fe-Mn oxide bound fractions in P4 and G1 treated soil, thereby reducing the phytoavailability and bioaccessible of heavy metal(loid)s. This research provides alternatives method to treat water and soil containing high concentrations of multi-heavy metal(loid)s.

Synergetic effect between zeolite 5 A and maghemite nanoparticles for fast lead uptake from the Peruvian river Cumbaza: Study of surface adsorption mechanism using X-ray photoelectron spectroscopy

A novel magnetic composite of zeolite 5A and maghemite nanoparticles has been synthesized at 300 K and its lead removal properties from the Peruvian river Cumbaza were systematically studied. Its kinetic adsorption properties were investigated, and a fast equilibrium time of 15 min was achieved with 97% of removal and an adsorbent dose of 0.5 g L−1. A 100% Pb removal efficiency was reached by increasing the adsorbent dose to 1.0 g L−1, which concomitantly also removed iron species from the river aliquots. During the kinetic tests, the optimum pH was from 6.5 to 7.5, showing that no chemical reactant alteration was required to achieve a remarkable efficiency for the magnetic composite. The kinetic adsorption behavior matched well with the pseudo-first and second-order models. Post-adsorption analysis confirmed the presence of lead in all the samples. The combined results also demonstrated a synergetic response between lead and both adsorbent phases. The adsorption mechanism was governed by three steps, including inner surface complexation between lead species and maghemite, followed by lead cationic exchange between calcium-bulk and sodium-surface from zeolite 5A. Hence, this novel magnetic adsorbent exhibits a high lead removal efficiency, and it is easy-to-handle separation properties in real effluents.

Removal and emission characteristics of hazardous trace elements in total and graded particulate matters: A case study of a typical ultra-low emission coal-fired power plant

Particulate matters (PMs) and hazardous trace elements (HTEs) emitted from coal-fired power plants (CFPPs) have raised serious environmental and human issues. Herein, total PMs and graded PMs including PM<1, PM1–2.5 and PM2.5–10 at the inlet/outlet of air pollution control devices (APCDs) were collected from a representative ultra-low emission (ULE) CFPP in China. The removal efficiencies of total PMs by selective catalytic reduction (SCR), electrostatic precipitator (ESP), wet flue gas desulfurization (WFGD) and wet electrostatic precipitator (WESP) were 0.40 %, 99.9 %, 38.1 % and 85.3 %, respectively. PM2.5–10 was robustly removed by WFGD, while PM<1 and PM1–2.5 were readily removed by WESP. The removal efficiencies of As, Cd, Cr and Pb in total PMs by APCDs followed an order: ESP > WESP > WFGD > SCR. SCR significantly decreased Se concentration by 42.8 %, contrasting to the removal of As, Cd, Cr and Pb (10.8–20.8 %). As, Cd, Cr, Pb and Se concentrations in graded PMs at the outlets of ESP, WFGD and WESP decreased with particle size increasing. All As, Cd, Cr, and Pb contents in PM<1, PM1–2.5 and PM2.5–10 at WFGD outlet increased, surpassing their analogues at ESP and WESP outlets. However, the concentration of Se declined in PM<1 at WFGD outlet. The atmospheric emission factors (EFs) of As, Cd, Cr, Pb and Se in the studied ULE CFPP were respectively 7.32, 1.27, 6.05, 122.5 and 6.42 mg/t, in line with Monte Carlo simulations. This study would not only provide a basis for emission control of PMs and HTEs in CFPPs, but also promote the improvement of respective environmental policy.

Sodium bicarbonate-hydroxyapatite used for removal of lead ions from aqueous solution

This study reports the development of a novel biocomposite for potential applications in the environmental remediation. The hydroxyapatite/sodium bicarbonate (HAp-SB) biocomposite obtained by a cheap method could offer promising characteristics to be used in environmental applications. The obtaining of HAp-SB ceramic composites was studied with the aim of increasing the adsorption efficiency of lead ions from contaminated waters. A composite material (HAp-SB) with good crystallinity that preserves the hexagonal structure of pure hydroxyapatite was obtained. For the powder recovered after decontamination of the lead solution (PbHAp-SB), the XRD model highlighted additional maxima belonging to Ca10(PO4)5(OH)2, Ca0.805Pb4.195(PO4)(OH) and PbH2P2O7. The FTIR spectra of PbHAp-SB are similar to those of HAp-SB composites showing a broadening of the vibration peaks and a slight shift. The XPS and EDS studies illustrated the purity of the HAp-SB sample. Moreover, the presence of lead in the powder recovered after decontamination was also highlighted by XPS and EDS studies. The efficiency of HAp-SB in the adsorption of Pb2+ ions from the contaminated solution was also highlighted by ultrasound studies using double-distilled water as the reference liquid. The adsorption kinetics were investigated with the aid of Langmuir and Freundlich theoretical models. The results demonstrated that the HAp-SB ceramic composite has a strong affinity for the adsorption of Pb2+ ions from contaminated solutions. The removal efficiency of Pb2+ ions was about 92% for the initial Pb2+ concentration above 50 mg/L. The results of the cell viability and cytotoxicity studies demonstrated that HAp-SB nanoparticles did not influence negatively the HeLa cell's viability and did not induce any significant changes of the morphological features of HeLa cells after 24 h of incubation. The batch adsorption results as well as the cytotoxicity assay results suggested that the HAp-SB powder could be successfully used for the removal of Pb2+ from contaminated water.

Study on Cu- and Pb-contaminated loess remediation using electrokinetic technology coupled with biological permeable reactive barrier

Although the electrokinetic (EK) remediation has drawn great attention because of its good maneuverability, the focusing phenomenon near the cathode and low removal efficiency remain to be addressed. In this study, a novel EK reactor was proposed to remediate Cu and Pb contaminated loess where a biological permeable reactive barrier (bio-PRB) was deployed to the middle of the EK reactor. For comparison, three test configurations, namely, CG, TG-1, and TG-2, were available. CG considered the multiple enzyme-induced carbonate precipitation (EICP) treatments, while TG-1 considered both the multiple EICP treatments and pH regulation. TG-2 further considered NH4+ recovery based on TG-1. CG not only improved Cu and Pb removals by the bio-PRB but also depressed the focusing phenomenon. TG-1 causes more Cu2+ and Pb2+ to migrate toward the bio-PRB and aggravates Cu and Pb removals by the bio-PRB, depressing the focusing phenomenon. TG-2 depressed the focusing phenomenon the most because Cu2+ and Pb2+ can combine with not only CO32− but PO43−. The removal efficiency of Cu and Pb is 34% and 36%, respectively. A NH4+ recovery of about 100% is attained.

Functionalized UiO-67-Rhodanine-3-acetic acid (Rd) composites efficiently trapping Pb (II) in wastewater

Metal organic frameworks (MOFs) have the advantages of large specific surface area, high porosity, controlled structures and strong stability, and were excellent adsorbents for the efficient trapping of heavy metals. In this work, two morphologies of Zr-MOF composites (UiO-67-AC-Rd and UiO-67-FA-Rd) under different solvent conditions were synthesized by a sequential solvothermal process. The properties of the composites were characterized by SEM, TEM, XRD, XPS, and BET, and the adsorption capacities of Pb (II) were investigated in detail. The excellent performance of UiO-67-AC-Rd exhibited superfast removal efficiencies for Pb (II), ascribing to its surface contains plentiful oxygen, nitrogen and sulfur functional groups and large specific surface area, which makes it have fascinating properties in removing Pb (II), and the maximum adsorption capacity of Pb (II) was 309.8 mg g−1. Chelation and electrostatic adsorption were considered as the main adsorption mechanisms. Adsorption isotherms were fitted well using the Langmuir and Freundlich model, and the adsorption thermodynamics indicated that the adsorption process was endothermic and spontaneous. The UiO-67-AC-Rd composites maintained excellent adsorption capacity for Pb (II) after four consecutive cycles, and the removal efficiency was above 74 %. The study will further provide a new pathway to the application of UiO-67-Rd composites in the adsorption of heavy metals in wastewater.

Highly efficient removal of trace heavy metals by high surface area ordered dithiocarbamate-functionalized magnetic mesoporous silica.

The study describes synthesizing and characterizing a novel dithiocarbamate-functionalized magnetic nanocomposite. This nanocomposite exhibits several desirable properties, including a large pore diameter of 2.55 nm, a high surface area of 1149 m2/g, and excellent capturing capabilities. The synthesis process involves the preparation of highly porous magnetic nanocomposites, followed by functionalization with dithiocarbamate functional groups through a reaction with carbon disulfide and amine. The synthesized nanocomposite was thoroughly characterized using various techniques, including X-ray diffraction analysis, transmission electron microscopy, scanning electron microscopy, Fourier-transform infrared spectroscopy, and thermogravimetric analysis. The performance of the mesoporous nanocomposite as an adsorbent for removing Pb(II), Cd(II), and Cu(II) cations from contaminated water was evaluated. The study finds that the maximum removal efficiency for Pb(II), Cd(II), and Cu(II) cations is achieved at pH values above 4. The optimal contact time for achieving 100% removal efficiency of the mentioned cations ranged between 60 and 120 min. Within this time range, the adsorbent exhibited efficient capture of the heavy metal cations from contaminated water. Additionally, the appropriate amount of adsorbent required for complete elimination of the heavy metal cations is determined. For Cd(II), the optimal dosage was found to be 50 mg of the adsorbent. For Cu(II), the optimal dosage was determined to be 40 mg. Finally, for Pb(II), the optimal dosage was 30 mg. The adsorbent's regeneration capability was demonstrated, showing that it could be reused for five consecutive runs.

Dissolved Lead Removal from Soil-washing Process Using Electrocoagulation

Soil-washing using ethylenediamine-tetraacetate (EDTA) is an effective method for the remediation of lead (Pb) contaminated land. In practice, it is necessary to manage wastewater from this remediation process. The Electrocoagulation technique is an alternative method to remove Pb from soil-washing wastewater. The primary purpose of this study is to determine optimum conditions for the electrocoagulation process of Pb removal from soil-washing wastewater. This study used an electrochemical batch reactor with a monopolar parallel circuit. Based on the initial research, the Pb concentration in soil-washing wastewater was 3600 mg/L. Several parameters were used to obtain the optimal condition for Pb removal: operational voltage, type of electrode used, and time. The result showed that the optimum condition for Pb removal is on the operational voltage of 7 volt (V), using aluminium electrode pair, at an operating time of 80 min within the Pb removal efficiency of 96%. Furthermore, the kinetics study showed the highest Pb precipitation was 0.041/min following the first-order model. Using these optimal parameters, the Pb precipitation and removal efficiencies for real soil-washing wastewater were 0.0416/min and 96.7%, respectively. The electrocoagulation method is efficient for simultaneously removing lead from polluted effluents.

Adsorption Performance of Walnut Green Husk Biochar for Heavy Metals

The biochars of WP300, WP500, and WP700 were prepared by pyrolyzing walnut green husk under 300℃, 500℃, and 700℃ with the oxygen-free condition for removing Pb2+, Cu2+, and Cd2+ in an aqueous solution. The results revealed that WP500 prepared under the medium pyrolysis temperature achieved the best adsorption performance for heavy metals, and the highest removal efficiency was reached when the solution pH was 8, in which the removal efficiency of Pb2+, Cu2+, and Cd2+ were 97.87%, 99.78%, and 71.15%, respectively. The required biochar dosage for heavy metal removal varied under different adsorption conditions. In the single-metal system, the optimal dosage for WP500 in the Pb2+, Cu2+, and Cd2+ solutions was 1.3 g·L-1, 2.1 g·L-1, and 1.9 g·L-1, respectively, whereas in the pollution metals system, the optimal biochar dosage was 5.1 g·L-1. In addition, the adsorption capacity of WP500 for the three heavy metals followed the order of Pb2+>Cu2+>Cd2+ under the single and combined-metals system, indicating that there were no synergistic or antagonistic effects among these three adsorbates. The fitting results of the adsorption isotherm model suggested that various immobilization methods existed in adsorption process between WP500 and Pb2+, Cu2+, and Cd2+. The kinetic fitting results suggested that the main reaction between WP500 and Pb2+, Cu2+, and Cd2+ was chemical adsorption. The mechanisms of WP500 for heavy metals involved pore-filling, electrostatic attraction, ion-exchange, mineral precipitation, complexation, and π-π electron donor-accepter interaction. To conclude, this study offered a new insight for the resource utilization of the waste walnut green husk.

Removal of Cadmium and Lead from Synthetic Wastewater Using Galdieria sulphuraria

The strain of red microalgae Galdieria sulphuraria CCMEE 5587.1 was evaluated in a controlled laboratory environment for its ability to tolerate and remove two heavy metal (HM) ions: cadmium [Cd(II)] and lead [Pb(II)] in aqueous solutions as a single metal species. Various concentrations (0 mg L−1 to 5 mg L−1) of Cd and Pb ions were added to the Cyanidium medium in which the chosen microalgae strain G. sulphuraria CCMEE 5587.1 was grown at an acidic pH of 2.5. The effectiveness of G. sulphuraria CCMEE 5587.1 in tolerating and removing these two metal ions was measured by analyzing its growth profile, growth rate, nutrient removal, and metal ion removal efficiency. The growth of G. sulphuraria CCMEE 5587.1 was inhibited during the initial days of incubation, and the growth rate decreased when the HM concentration in the media was increased. Nutrient removal in the HM-containing media is comparable to that in the control media at low metal concentrations but decreases as the metal concentration rises. G. sulphuraria CCMEE 5587.1 has the highest removal efficiency for Cd and Pb in a medium containing 2.5 mg L−1 of metal ions, which is 49.80% and 25.10%, and the corresponding sorption capacity is 1.45 mg g−1 and 0.53 mg g−1 of dry biomass, respectively. These findings suggest that G. sulphuraria CCMEE 5587.1 holds potential as a viable bioremediation solution for extracting Cd and Pb from wastewater, alongside its capacity to remove nutrients concurrently. The study underscores the dual advantage of G. sulphuraria CCMEE 5587.1, making it a promising candidate for addressing heavy metal pollution in wastewater treatment processes.

A comparison of adsorption capacity of several synthesis methods of cellulose-based absorbent towards Pb(II) removal: Optimization with response surface methodology

The effects of various synthesis methods of a novel biodegradable magnetically recyclable cellulose-based adsorbent (a magnetized modified silica aerogel) on Pb(II) removal efficiency were studied. QSM (quince seed mucilage) was modified via hydrothermal and ultrasonic modes. Oven-drying and freeze-drying procedures were then used to obtain the final adsorbents. The adsorbents were named A1 to A4 and B1 to B4, depending on the synthesis and drying techniques. XRD, FTIR, BET, and SEM are characterization techniques for identifying the adsorbents. Average crystallite sizes of 15.5, 8.3, 10.9, and 2.7 nm were obtained for A1, A2, A3, and A4 samples (Scherrer formula). SEM image confirmed a Sticky bullets-like morphology. The pHpzc values of 3.4, 6.0, and 4.1 were also determined for Fe-silica aerogel, Fe-QSM, and Fe-silica aerogel-QSM samples. The highest adsorption efficiency of the A2 adsorbent towards Pb(II) cations was followed via the experimental design by the RSM (response surface methodology) approach. ANOVA results showed model F value 185 (>F0.05, 14, 15 = 2.42) and LOF F-value of 0.3831 (<F0.05, 10, 5 = 4.74) at a 95 % confidence interval. The center point run conditions were catalyst dose: 7 g/L, pH: 3.2; CPb: 11 mg/L, and contact time: 55 min, while the optimal run conditions were adsorbent dose: 1.0 g/L; pH: 2.6; CPb: 7 mg/L; and contact time: 80 min with about 94 % Pb(II) removal efficiency. The adsorption mechanism was studied, and correlation coefficient (R2) values of Langmuir (0.9814), Freundlich (0.9328), Temkin (0.8898), and Redlich-Peterson (0.9977). They have recommended that the adsorption process fit best with the Langmuir and Redlich-Peterson models. A kinetic study revealed that adsorption was well described by pseudo-second-order kinetics. The thermodynamic studies showed a spontaneous and endothermic adsorption process.

Cotton-based bionic tree-shaped photothermal evaporator for extraction of heavy metals from river sediment

Pollution of river sediments with heavy metals poses significant threats to both ecological and human health. Thus, in-situ extraction of heavy metals from sediments has emerged as a challenging and important research issue. To address this issue, a cotton-based bionic tree-shaped photothermal evaporator was designed to enhance water evaporation and facilitate heavy metals extraction from sediment porewater. The evaporator demonstrated a remarkable evaporation flux of 3.25 kg m-2 h-1 under 1 sun illumination. Over a 28-day solar-driven evaporative remediation (SDER) process, the removal efficiencies of total Pb and Cd were 17.4% and 29.9%, respectively. Importantly, the bioavailable fractions of residual Pb and Cd were also reduced by 46.3% and 25.0%, respectively. Furthermore, cabbage cultivation experiments to assess the practical efficacy of SDER showed that accumulation of Pb and Cd in cabbage roots was decreased by 66.0% and 46.3%, respectively, and accumulation in shoots was decreased by 57.2% and 55.7%, respectively. Thus, SDER was demonstrated to effectively reduce biological toxicity in sediment. This study introduces a novel approach that efficiently utilizes sunlight for the rapid extraction of heavy metals from sediment, presenting a promising general strategy for the low energy remediation of heavy metals-contaminated sediments.

Accelerated Pb(II) removal and concurrent bioelectricity production via constructed wetland-microbial fuel cell: Structural orthogonal optimization and microbial response mechanism

In this study, a novel constructed wetland-microbial fuel cell (CW-MFC) filled with biomass carbon sources was established to elucidate the impacts of orthogonal configuration of multiple constraints towards wastewater purification and bioelectricity generation under Pb(II) stress. As a result, the optimal structural layouts of CW-MFC were granular activated carbon, Iris pseudacorus and 20 cm of electrode spacing, respectively. The homologous system yielded a favorable Pb(II) removal efficiency of 99.05 %, a maximum output voltage of 394.3 mV and power density of 4468.40 mW/m2, respectively. The migration results highlighted the major contribution of substrate and biomass to Pb(II) adsorption and fixation. Likewise, Pb(II) was immobilized on the cathode via potential binding to O. A visible enrichment of electroactive bacteria (Clostridium, Geobacter, Pseudomonas) and metal-resistant bacteria (Novosphingobium, Aeromonas) was noted. Also, microorganisms modulated the intracellular transport, chemotactic and antioxidant systems by engaging in the metabolic processes of carbohydrate, glutathione, pyruvate, etc. The microbial analysis signified that the genera enriched in disparate regions of CW-MFC-6 regulated the metabolic processes to facilitate their activities and resistance to Pb(II) stress, thereby synergistically enhancing the integrated capability of closed-circuit device. This study was dedicated to elucidating the microbial response mechanism of structural orthogonal optimization of CW-MFC, and providing a theoretical guidance for an effective regulation of Pb(II)-containing wastewater treatment.

Biosorption of Pb(II) Using Natural and Treated Ardisia compressa K. Leaves: Simulation Framework Extended through the Application of Artificial Neural Network and Genetic Algorithm.

This study explored the effects of solution pH, biosorbent dose, contact time, and temperature on the Pb(II) biosorption process of natural and chemically treated leaves of A. compressa K. (Raw-AC and AC-OH, respectively). The results show that the surface characteristics of Raw-AC changed following alkali treatment. FT-IR analysis showed the presence of various functional groups on the surface of the biosorbent, which were binding sites for the Pb(II) biosorption. The nonlinear pseudo-second-order kinetic model was found to be the best fitted to the experimental kinetic data. Adsorption equilibrium data at pH = 2-6, biosorbents dose from 5 to 20 mg/L, and temperature from 300.15 to 333.15 K were adjusted to the Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherm models. The results show that the adsorption capacity was enhanced with the increase in the solution pH and diminished with the increase in the temperature and biosorbent dose. It was also found that AC-OH is more effective than Raw-AC in removing Pb(II) from aqueous solutions. This was also confirmed using artificial neural networks and genetic algorithms, where it was demonstrated that the improvement was around 57.7%. The nonlinear Langmuir isotherm model was the best fitted, and the maximum adsorption capacities of Raw-AC and AC-OH were 96 mg/g and 170 mg/g, respectively. The removal efficiency of Pb(II) was maintained approximately after three adsorption and desorption cycles using 0.5 M HCl as an eluent. This research delved into the impact of solution pH, biosorbent characteristics, and operational parameters on Pb(II) biosorption, offering valuable insights for engineering education by illustrating the practical application of fundamental chemical and kinetic principles to enhance the design and optimization of sustainable water treatment systems.

Evaluation of efficiency of Wheat straw nanocellulose as nanoadsorbent for the removal of divalent copper, lead and zinc from aqueous solution

Novel nanocellulose (cellulosic carbohydrate polymer) embedded with Wheat straw was synthesized, characterized and examined as nanoadsorbent for the removal of copper, lead and zinc metals from aqueous solution through batch mode. The effects of pH, dose, contact time, temperature and synchronous cations on the amount of Cu (II), Pb (II) and Zn (II) adsorbed have been probed. The desirable pH was 8 and nanoadsorbent dose was 0.6 g/50 mL in the adsorption study. The removal efficiencies of Cu (II), Pb (II) and Zn (II) were 88.75%, 81.18%, 86.84% respectively. Adsorption kinetic study was employed to analyze experimental data and adsorption process followed pseudo second order kinetic model. Langmuir, Freundlich, Temkin and Redlich-Peterson isotherm models were used to indicate the adsorption of Cu (II), Pb (II) and Zn (II) on WSN and thermodynamic study affirmed that adsorption process was endothermic and spontaneous. AFM indicated size and morphology and attachment of functional groups on WSN were examined by FTIR. The results confided that adsorption is economically competent method for removing Cu (II), Pb (II) and Zn (II) and WSN is anticipative owing to its ease and low cost of regeneration

Removal of Pb(II) from Aqueous Solution and Adsorption Kinetics of Corn Stalk Biochar

In this work, the Pb adsorption and removal ability of biochar from simulated Pb(II)-contaminated wastewater, adsorption isotherms, kinetics, and thermodynamics were studied. Adsorption characteristics of biochar on Pb(II) were analyzed by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and scanning electron microscope with energy dispersive spectrometer (SEM-EDS). The influence of the pH of the solution, the contact time, and the biochar dose on the removal of Pb(II) were investigated by single-factor design and response surface analysis. With the increase in biochar dose from 2 g/L to 4 g/L in wastewater, the Pb(II) amount adsorbed on biochar reduced from 21.3 mg/g to 17.5 mg/g. A weakly acidic environment was more conducive to the ligand exchange between Pb(II) ions and biochar. Pb(II) adsorption kinetics of biochar showed that the Pseudo-first-order model was more suitable than other employed models to describe the adsorption process. During the isothermal adsorption process, Langmuir and Freundlich’s isotherms fitted the adsorption data very well (R2 &gt; 96%). The Pb (II) adsorption onto biochar was spontaneous in the specified temperature range (298–318 K) and the process was exothermic. Simultaneously, the optimal conditions were a pH of 5, a contact time of 255 min, and a biochar dose of 3 g/L, under which the maximum predicted Pb(II) removal efficiency was 91.52%.

A pilot trial in the remediation of pollutants simultaneously with bioenergy generation through microbial fuel cell

Microbial fuel cell (MFC) is one of the popular approaches to degrading pollutants while generating energy. This study highlights a new idea for the scientific community by treating organic and inorganic pollutants simultaneously in addition to energy generation. To date, no attempt at the treatment of a dual-pollutant system (organic and inorganic) via MFC has been reported. Similarly, the use of palm sugar as an organic substrate is also reported for the first time in this work. Palm sugar is found to be a promising solution to address the challenges in the selection of organic substrates for MFC. The achieved power density was 130.26 mW/m2 within 44 days of operation. The removal efficiency of Pb2+ was 88% while the biodegradation efficiency of resorcinol was 93.50%. Electrochemical studies revealed a specific capacitance of 1.7 × 10−4 F/g and a total internal resistance of 717.17 Ω (Rs = 685.97 Ω and Rct = 31.20 Ω) on the 80th day. As a result of 16 S rRNA sequencing and primary isolation, it was found that Bacillus and Pseudomonas are species that dominate the anode surface and are involved in pollution remediation. The present study also investigates the fundamental biodegradation and oxidation mechanisms of pollutants as well as the organic substrate. In addition, the most concerning challenges to this technique`s commercialization are also briefly discussed.