Adsorption Of Lead Ions Research Articles

Synergic binding of rhodamine-B and heavy metal ions onto polyethyleneimine grafted freeze-dried chitosan/epichlorohydrin composite beads and possible mechanism

This paper reports a synergic binding technique of dye and cadmium/lead ions onto freeze-dried modified chitosan beads (GCCS), in this work modified chitosan beads was applied in binary solution. Chitosan beads (CS) composite was produced and polyethyleneimine was grafted onto the backbone of the developed composite. The beads were analyzed utilizing different analytical techniques such as Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscope (SEM). The model applied in pH equilibrium was found to justify the adsorption of pollutants onto the adsorbent. The model was established from 2 equilibrium calculations, one justifying the acid-base attributes of the modified beads, the other elucidating the adsorption of the adsorbates onto the beads, and a mass balance of the various arrangement of nitrogen in the adsorbent. The excellent fit of the Pseudo-second order and intra-particle diffusion kinetic model shows that chemical binding might be the rate-limiting step. The adsorption isotherms were well represented by the Langmuir and Temkin models at a temperature of 45 °C. The maximum binding capacities (Qmax) from the Langmuir model were observed to be 390, 315 and 278 mg/g for the adsorption of dye, lead and cadmium ions respectively`. However, it was found to be higher in the binary system with the same applicable conditions. The correlation was analyzed utilizing various models and lines of best fit were obtained. Synergic effect was observed from the experimental results acquired from the adsorption of Rhodamine B (RHB) and adsorbates. These findings show the formation of fresh binding sites during simultaneous binding process.

Development of cellulose/hydroxyapatite/TiO2 scaffolds for efficient removal of lead (II) ions pollution: Characterization, kinetic analysis, and artificial neural network modeling

The utilization of nano-biodegradable composites for removing pollutants and heavy metals in aquatic environments has been widespread. This study focuses on synthesizing cellulose/hydroxyapatite nanocomposites with titanium dioxide (TiO2) via the freeze-drying method for the adsorption of lead ions in aquatic environments. The physical and chemical properties of the nanocomposites, including structure, morphology, and mechanical properties, were analyzed through FTIR, XRD, SEM, and EDS. In addition, parameters affecting the adsorption capacity, such as time, temperature, pH, and initial concentration, were determined. The nanocomposite exhibited a maximum adsorption capacity of 1012 mg⸱g−1, and the second-order kinetic model was found to govern the adsorption process. Additionally, an artificial neural network (ANN) was created using weight percentages (wt%) of nanoparticles included in the scaffold to predict the mechanical behavior, porosity, and desorption of the scaffolds at various weight percentages of hydroxyapatite (nHAP) and TiO2. The results of the ANN indicated that the incorporation of both single and hybrid nanoparticles into the scaffolds improved their mechanical behavior and desorption, as well as increased their porosity.

Effect of polylactic acid microplastics and lead on the growth and physiological characteristics of buckwheat

Microplastics (MPs) and heavy metals are common, often co-existing pollutants, that threaten crop growth and productivity worldwide. We analysed the adsorption of lead ions (Pb2+) to polylactic acid MPs (PLA-MPs) and their single factor and combined effects on tartary buckwheat (Fagopyrum tataricum L. Gaertn.) in hydroponics by measuring changes in the growth characteristics, antioxidant enzyme activities and Pb2+ uptake of buckwheat in response to PLA-MPs and Pb2+. PLA-MPs adsorbed Pb2+, and the better fitting second-order adsorption model implied that Pb2+ was adsorbed by chemisorption. However, the similar Pb2+ contents in the plants treated with Pb2+ only and those treated with the combined PLA-MPs-Pb2+ suggested that the adsorption played no role in the uptake of Pb2+. Low concentrations of PLA-MPs promoted shoot length. At high concentrations of both PLA-MPs and Pb2+, buckwheat growth was inhibited, and leaf peroxidase (POD), superoxide dismutase (SOD) and catalase (CAT) activities and malondialdehyde (MDA) contents were higher than in the control. No significant differences were observed in seedling growth between exposure to Pb2+ only and combined exposure to PLA-MPs with Pb2+, implying that PLA-MPs did not increase the toxicity of Pb2+ at macroscopic level. POD activity was higher and chlorophyll content was lower with PLA-MPs in the low Pb2+ dose treatments, suggesting that PLA-MPs may increase the toxicity of naturally occurring Pb2+. However, the conclusions must be verified in controlled experiments in natural soil conditions over the whole cultivation period of buckwheat.

Fixating lead in coal gangue with phosphate using phosphate-dissolving bacteria: Phosphorus dissolving characteristics of bacteria and adsorption mechanism of extracellular polymer

Controlling and preventing lead pollution is currently the focus of environmental remediation. Coal gangue contains large quantities of lead, and its environmental impact cannot be ignored. This study investigated the tolerance of Stenotrophomonas maltophilia (YZ-1 train) to lead ion and its fixation effect on lead in coal gangue. The fixation mechanism of lead ions by using the YZ-1 train was studied with CaHPO4 and Ca3(PO4)2. The tolerance mechanism and fixation characteristics of the three bacterial extracellular polymers and cell components to lead were analyzed. The results show that the YZ-1 train had a strong resistance to lead ions. The amount of lead released from coal gangue can be reduced by up to 91.1% upon treatment with the YZ-1 train, which can dissolve phosphate minerals to form stable hydroxyapatite (Pb5(PO4)3(OH)) and pyromorphite (Pb5(PO4)3Cl) with lead ions. Tryptophan and tyrosine from cellular components and extracellular polymers with loosely and tightly bound proteins are the main participants in the fixation of lead ions. The by-products of soluble microbes affect the fixation of lead ions in soluble extracellular polymers. The carboxylic acids and carboxylates secreted by bacteria are involved in the adsorption and fixation of lead ions.

Removal of Metal Ions via Adsorption Using Carbon Magnetic Nanocomposites: Optimization through Response Surface Methodology, Kinetic and Thermodynamic Studies

The toxicity of metal ions on ecosystems has led to increasing amounts of research on their removal from wastewater. This paper presents the efficient application of a carbon magnetic nanocomposite as an adsorbent for the elimination of metal ions (copper, lead and zinc) from aqueous solutions. A Box–Behnken factorial design combined with the response surface methodology was conducted to investigate the effect and interactions of three variables on the pollutant removal process. Highly significant (p < 0.001) polynomial models were developed for each metal ion: the correlation coefficient was 0.99 for Cu(II) and Pb(II), and 0.96 for Zn(II) ion removal. The experimental data were in agreement and close to the theoretical results, which supports the applicability of the method. Working at the natural pH of the solutions, with a quantity of carbon magnetic nanocomposite of 1 g/L and a metal ions’ concentration of 10 mg/L, for 240 min, removal efficiencies greater than 75% were obtained. The kinetic study indicated that a combination of kinetic models pseudo-second order and intraparticle diffusion were applied appropriately for copper, lead and zinc ion adsorption on carbon magnetic nanocomposite. The maximum adsorption capacities determined from the Langmuir isotherm model were 81.36, 83.54 and 57.11 mg/g for copper, lead and zinc ions. The average removal efficiency for five adsorption–desorption cycles was 82.21% for Cu(II), 84.50% for Pb(II) and 72.68% for Zn(II). The high adsorption capacities of metal ions, in a short time, as well as the easy separation of the nanocomposite from the solution, support the applicability of the magnetic carbon nanocomposite for wastewater treatment.

Adsorption of Lead (II) Ions onto Goethite Chitosan Beads: Isotherms, Kinetics, and Mechanism Studies

Lead is a highly toxic heavy metal that creates a water pollutant. It can be released from industrial processes, agricultural chemistry, and community wastes, affecting creatures and human health even at a low concentration. As a result, it is advised that lead be removed before releasing wastewater into the environment. This study synthesized three chitosan bead materials from shrimp shell wastes which were chitosan powder beads (CB), chitosan powder mixed with goethite beads (CFB), and chitosan powder beads coated with goethite (CBF) for removing lead in an aqueous solution. Their surface area, pore volumes, and pore sizes were explored according to Brunauer– Emmett–Teller, and their crystalline formations were investigated using an X-ray diffractometer. Their surface structures were studied using field emission scanning electron microscopy and a focus ion beam, and their chemical compositions were determined using an energy dispersive X-ray spectrometer. Their chemical functional groups were identified via Fourier-transform infrared spectroscopy. In addition, batch experiments were conducted to investigate the effects of several factors on removing lead, and the adsorption isotherm and kinetics were also investigated for determining their adsorption pattern and mechanism. In addition, the desorption experiments were studied to confirm their possible material reusability. The CBF demonstrated the highest surface area and smallest pore size compared with the other materials. In addition, the pore sizes of the CFB and CBF were micropores, whereas those of the CB were mesopores. All materials were semicrystalline structures, and the specific goethite peaks were observed in the CFB and CBF. All materials had spherical shapes with heterogeneous surfaces. Six chemical components of O, C, Ca, N, Cl, and Na were discovered in all materials, and Fe was only found in the CFB and CBF because of the addition of goethite. Five main chemical functional groups of N–H, O–H, C–H, C–O, and –COOH were found in all materials. The optimum conditions of the CB, CFB, and CBF for removing lead were 0.5 g, 16 h, pH 5, 0.5 g, 16 h, pH 5, and 0.4 g, 14 h, pH 5, respectively. The results of the batch experiments demonstrated that the CB, CFB, and CBF were high-efficiency adsorbents for removing lead in solution by more than 95%, whereby the CBF showed the highest lead removal of 99%. The Freundlich isotherm model and pseudo-second-order kinetic model helped to well explain their adsorption pattern and mechanism. The maximum lead adsorption capacities of the CB, CFB, and CBF were 322.58, 333.33, and 344.83 mg/g, respectively. Furthermore, all chitosan materials can be reused for more than three cycles with high lead removal by more than 94%; so, they are potential materials for application in industrial applications.

Optimization of Copper, Lead and Nickel Ions Adsorption by Melia azedarach Activated Carbon: A Response Surface Methodology Approach

Optimization of Copper, Lead and Nickel Ions Adsorption by Melia azedarach Activated Carbon: A Response Surface Methodology Approach

Experimental and theoretical investigation of lead ion adsorption from the synthetic wastewater using the biosorbent derived from Cardita bicolor shell

Experimental and theoretical investigation of lead ion adsorption from the synthetic wastewater using the biosorbent derived from Cardita bicolor shell

Cellulose derivatives functionalized with multidentate N‑donor atoms: comparative adsorption of cadmium (II) and lead (II) ions from water

Cellulose derivatives functionalized with multidentate N‑donor atoms containing two, three and four amino functional groups (as marked N2–CL, N3–CL and N4–CL) have been prepared by grafting of linear aliphatic polyamines into the cellulose backbone through the Schiff base reaction. An increase in the adsorptive amounts of Cd2+ and Pb2+ with increasing N‑donor atoms of the grafted polyamines onto the cellulose backbone and the maximum capacity of N4–CL > N3–CL > N2–CL are found. The N4–CL with the highest N content (up to 5.2 mmol N g−1) exhibits the largest adsorptive capacities of 249.7 mg g−1 for Cd2+ and 401.2 mg g−1 for Pb2+. The adsorption of both the ions by the three cellulose derivatives is achieved within 30 min, is independent of pH in the range of 4.5–6 for Cd2+ and 4–6 for Pb2+, and can be satisfactorily fitted by Langmuir and pseudo-second-order equations. Thermodynamic parameters suggest an endothermic and endothermic nature.

Adsorption of lead ions by magnetic carbon: Comparison of magnetic carbon properties and modification methods

Magnetic biochar (MBC) is extensively used to remove contaminants from environmental media because of being easy to recover and separate. However, magnetic modification generally decreases the surface area of Biochar (BC), leading to an insignificant improvement in adsorption performance. In the present study, research was conducted on the changes in the physicochemical characteristics of the modified MBC in terms of elemental distribution, morphological characteristics, and surface functional groups based on magnetic carbon. Magnetic carbon was prepared using pine cone material and modified by four methods (ball milling, acid and oxidant modifications as well as metal impregnation). The role of contact time (0.25–8 h), initial Pb2+ concentration (5–200 mg/L), solution pH (2-7), and other process parameters in removing Pb2+ from the contaminated water was evaluated. The results showed that the maximum adsorption of Pb2+ by MBC reached up to 123.38 mg/g when time varied from 0.25 to 8 h. The proposed secondary kinetic and Langmuir isotherm models better proved the results of adsorption. The adsorption performance of ball milling modified MBC (BMBC) was evenly enhanced to varying degrees by several modification methods, especially ball milling with green and low-cost, a simple mechanical process to enhance the number and surface area of functional groups of MBC.

Optimization of batch study parameters for the adsorption of lead(II) ions onto spent tea grains

Abstract The present study aims to investigate the use of response surface methodology (RSM) modelling and experimental investigation for the optimization of lead(II) adsorption onto spent tea grains (STG). Independent process variables were optimized and found to be in the range of 38.75 mg/l (initial concentration), 5.20655 (pH), 119.32 rpm (stirring speed), and 3.25 g/l (STG dose) for a contact time of 135.05 min. The optimum adsorption capacity was found to be 8.9087 mg/g through RSM modelling with a maximum of 18.146 mg/g. The batch study was performed by varying different parameters: pH (2.0–7.0), initial concentration (5–50 mg/l), dose (0.1–1 g/100 ml), contact time (15–180 min), and stirring speed (30–200 rpm). The characterization STG was done by proximate and ultimate analysis, FTIR spectroscopy, XRD analysis, thermogravimetric analysis (TGA), and SEM-EDX. By fitting equilibrium data onto Langmuir isotherm model, the maximum adsorption capacity was found to be 24.272 mg/g. The optimum pH found for lead(II) adsorption onto STG was 5. At optimum conditions, the maximum removal efficiency of STG for lead(II) ions’ adsorption is 94.33%. Based on the findings it is safe to conclude that the STG could be used as a potential adsorbent.

Application of Alumina Nanofibers as Adsorbents for the Removal of Mercury (II) and Lead (II) from Aqueous Solutions

This study aims to design novel amine-functionalized alumina nanofibers for the removal of lead (II) and mercury (II) ions from aqueous solutions. The γ-Al2O3 nanofibers were prepared by calcination of boehmite, and then functionalization with 3-(2-aminoethylamino) propyl trimethoxy silane. The characterization of the nanofibers was carried out using TEM, EDS, elemental mapping, XRD, and XPS. The effects of initial concentration, pH, contact time, and selectivity were studied. The results revealed that the nanofibers can remove 98% of Hg2+ ions and 90% of Pb2+ ions from aqueous solution at concentrations of 40 mg/L and 35 mg/L, respectively. Additionally, the optimal pH conditions for mercury and lead ion adsorption were established to be 6. It was also observed that for concentrations of 100 mg/L and 250 mg/L, the majority of ion contaminants were removed by the nanofibers within the first hour. The adsorption capacities were found to be 129 mg/g and 165 mg/g for Hg2+ and 72.3 mg/g and 111 mg/g for Pb2+ at 100 mg/L and 250 mg/L concentrations, respectively. The ion-adsorption kinetic data was best fitted to a pseudo-second-order model. High sorption capacities were also demonstrated when employed to selectively adsorb mercury (II) and lead (II) ions from aqueous solutions containing Zn2+, Mg2+, Cu4+, Sn4+, and Ni4+. Desorption tests were performed to explore the stability of the heavy metals on the nanofiber.

Eco-Friendly Electroless Template Synthesis of Cu-Based Composite Track-Etched Membranes for Sorption Removal of Lead(II) Ions

This paper reports the synthesis of composite track-etched membranes (TeMs) modified with electrolessly deposited copper microtubules using copper deposition baths based on environmentally friendly and non-toxic reducing agents (ascorbic acid (Asc), glyoxylic acid (Gly), and dimethylamine borane (DMAB)), and comparative testing of their lead(II) ion removal capacity via batch adsorption experiments. The structure and composition of the composites were investigated by X-ray diffraction technique and scanning electron and atomic force microscopies. The optimal conditions for copper electroless plating were determined. The adsorption kinetics followed a pseudo-second-order kinetic model, which indicates that adsorption is controlled by the chemisorption process. A comparative study was conducted on the applicability of the Langmuir, Freundlich, and Dubinin-Radushkevich adsorption models to define the equilibrium isotherms and the isotherm constants for the prepared composite TeMs. Based on the regression coefficients R2, it has been shown that the Freundlich model better describes the experimental data of the composite TeMs on the adsorption of lead(II) ions.

Ecofriendly synthesis of hydrated manganese oxide and its efficient adsorption of lead ions from water

Abstract Utilizing the waste liquid derived from graphene oxide synthesis as raw material, hydrated manganese oxide (HMO) was prepared by a chemical precipitation method with sodium hydroxide solution or aqueous ammonia solution. The HMO samples were analyzed by X-ray diffraction, Fourier transform infrared spectroscopy, Zeta potential analyzer, and scanning electron microscopy. The adsorption characteristics of the HMO samples were examined through lead ion adsorption from water. The effects of adsorption temperature, starting lead ion concentration, and adsorption time on the lead ion adsorption capacity were investigated. The relevant data agreed well with the pseudo-second-order kinetic model and the Langmuir isotherm model. Additionally, the maximum adsorption capacities of HMO-1 are 70.897 mg g−1, 76.660 mg g−1, and 79.424 mg g−1 for the lead ions at 298 K, 308 K, and 318 K, respectively. The lead ion adsorption mechanism of HMO has been explained. The findings indicate the as-synthesized HMO can be used as an efficient adsorbent material for eliminating lead ions from water.

Graphene oxide/zeolitic imidazolate framework-8 nanocomposite for lead ion removal

Adsorption for heavy metal removal is extensively explored due to its economical and straightforward nature. In this study, the nanocomposites of graphene oxide (GO)/zeolitic imidazolate framework-8 (ZIF-8) adsorbents were prepared as adsorbents, with the solvent utilized was reverse osmosis (RO) water for a greener approach. Also, the synthesis was performed using the room temperature synthesis method which required less energy consumption. 10, 30, and 50 wt% GO were utilized to produce ZIF-8/GO composites of ZG1, ZG3, and ZG5, respectively. Based on the field emission scanning electron microscopy (FESEM) images, the adsorbents consisted of cubic and rhombic dodecahedron shapes of ZIF-8 grown on top and in between the layers of GO sheets. This inhibits the agglomeration nature of GO which increased the number of active sites, thus improving the lead ions adsorption capacity. From the batch tests conducted, ZG3 showed the greatest adsorption capacity of lead solution, followed by ZG5, ZG1, ZIF-8, and GO. The optimum conditions for adsorption using ZG3 were using the initial amount of lead solution of 20–100 mg/L at pH 5 to 6, and the sorbent dosage used was 10 mg. The equilibrium time obtained for lead adsorption was short, within 10 min for both ZG3 and ZG5. On the other hand, ZG1 reached equilibrium within 180, ZIF-8 within 240 min, and the longest time was GO, within 300 min. Therefore, ZG3 demonstrates a good potential as heavy metal adsorbent in wastewater treatment technology with ease of synthesis, sufficient amount of GO used, less dosage required, and shorter contact time needed.

Characterization and adsorption of raw pomegranate peel powder for lead (II) ions removal

The adsorption potential of raw pomegranate peel powder (PMPP) for lead (Pb) ions was investigated via batch mode at varying initial adsorbate concentration, contact time, and adsorbent concentration. The PMPP was extensively characterized using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy-dispersion X-ray (EDX), thermogravimetry (TG), and differential scanning calorimetry (DSC) analyses. The instrumental characterization results confirmed the presence of important functional groups and surface texture/morphology that played key roles during the lead ion adsorption. Description of the experimental equilibrium data by nonlinear Langmuir, Freundlich, Dubinin–Radushkevich, and Temkin isotherm models was elaborately presented in the study. The experimental kinetic data were fitted to the Pseudo-first-order, Pseudo-second-order, Intra-particle diffusion, and Elovich models. The Temkin model satisfactorily predicted the isotherm data. Meanwhile, the intra-particle diffusion model was best at predicting the kinetic data at adsorbate concentration of 150 mg/L, while the Elovich model emerged as the best fit at 300 mg/L concentration. This study shows that lead ions could be efficiently removed using raw pomegranate peel powder.

Adsorption of lead ions by activated carbon doped sodium alginate/sodium polyacrylate hydrogel beads and their in-situ recycle as sustainable photocatalysts

In this study, sodium alginate (SA), sodium polyacrylate (PAAS) and powdered activated carbon (PAC) were cross-linked by calcium ions [(Ca(II)] to form SA/PAAS/PAC (SPP) hydrogel beads. The hydrogel-lead sulfide (SPP-PbS) nanocomposites were successfully synthesized by in-situ vulcanization after the lead ions [(Pb(II)] adsorption. SPP showed an optimal swelling ratio (600% at the pH value of 5.0) and superior thermal stability (206 °C of heat-resistance index). The adsorption data of Pb(II) was compatible with the Langmuir model, and the maximum adsorption capacity of SPP was 391.65 mg/g after optimizing the mass ratio of SA to PAAS (3:1). The addition of PAC not only enhanced the adsorption capacity and stability, but also promoted photodegradation. The significant dispersive capacity of PAC and PAAS resulted in PbS nanoparticles with particle sizes of around 20 nm. SPP-PbS showed good photocatalysis and reusability. The degradation rate of RhB (200 mL, 10 mg/L) was 94% within 2 h and maintained above 80% after 5 cycles. The treatment efficiency of SPP was more than 80% in actual surface water. The results of quenching experiments and electron spin resonance (ESR) experiments revealed that the superoxide radicals (O2–) and holes (h+) were the main active species in the photocatalytic process.

Adsorption of lead ions and methylene blue on acrylate-modified hydrochars

Hydrochars are promising sorbents for wastewater treatment. Herein, two acrylate-modified hydrochars (AMHC1 and AMHC2) were obtained by grafting acrylic acid on the surface of two hydrochars (MHC1 and MHC2 hydrothermally carbonized in water and acidic medium respectively) with free radical polymerization. Characterizations show that MHC2 is more prone to free radical polymerization than MHC1 does, and has higher carboxylate content after modification. The adsorption amounts of AMHC2 over methylene blue (MB) and Pb(II) are much higher than those of AMHC1. Pseudo-second-order kinetic and Langmuir isotherm equations well fit the Pb(II) and MB sorption data of AMHC2. The Pb(II) adsorptive mechanism is mainly inner-surface complexation accompanied by ion exchange and cation-π interaction. MB adsorption involves ion exchange, electrostatic interaction, H-bonding and π-π interaction. Hence, the one-step modification method of free radical polymerization under alkaline condition has great potential for preparing carboxylate-modified hydrochars to adsorb cationic pollutants.

Effective removal of Pb(II) and Cu(II) from aqueous solutions using a hybrid composite of fuller's earth, aluminum silicate and chitosan

In this study, a highly effective hybrid adsorbent composite based on low-cost fuller’s earth (FE), aluminum silicate (AS) and chitosan (CS) was prepared using a facile method. The prepared composite was applied to adsorb lead (Pb2+) and copper (Cu2+) ions from aqueous solutions. Several analyses such as Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to characterize the composite. The adsorption efficiency of the prepared composite was investigated at different operating conditions. Moreover, the adsorption isotherm/kinetic models and adsorption thermodynamics of the composite were examined. The results showed that the pseudo-second-order kinetic model described well with the obtained data and the adsorption equilibrium can be better described by Langmuir isotherm model with maximum adsorption capacities of 305.5 and 284.2 mg/g for Pb2+ and Cu2+, respectively. The obtained data demonstrated that the prepared composite is an efficient and kinetically fast metal ion removal with high adsorption capacity and recovery efficiency.Graphical abstract

Isotherm, kinetics, thermodynamics, recyclability and mechanism of ultrasonic assisted adsorption of methylene blue and lead (II) ions using green synthesized nickel oxide nanoparticles

One of the urgent global problems demanding effective mitigation strategies is the pollution caused by organic dyes and metal ions like methylene blue and lead (II) ions. In recent times, the increasing applications of nickel oxide nanoparticles in biomedicine, catalysis, sensors in optoelectronic materials, and the prevention of environmental pollution have attracted researchers' interest across the globe. Herein, Psidium guajava leaves extract was utilized to synthesize green nickel oxide nanoparticles (PG-NiONPs). Surface and analytical techniques were employed to characterize PG-NiONPs and were thereafter applied to remove methylene blue and lead (II) ions from wastewater. The results revealed the quantified presence of phytochemicals such as alkaloids, phenols, tannins, flavonoids and saponins in the Psidium guajava leaves extract. The prepared PG-NiONPs revealed a crystalline phase, functional groups, mesoporous and microstructural arrangements typical of nickel oxide nanoparticles. The surface area of PG-NiONPs was obtained as 85.40 m2/g. The best ultrasonic-assisted adsorption of MB and Pb(II) ions was achieved at pH values of 6 and 5 for MB and Pb(II), a contact time of 60 min, an adsorbent mass of 40 mg/L, and a temperature of 50 °C, respectively. The maximum MB and Pb(II) adsorption capacities of 495.58 and 508.56 mg/g were evaluated. The experimental data corroborated with the pseudo-second-order and Toth isotherm models. The adsorption of MB and Pb(II) over green PG-NiONPs was a thermodynamically spontaneous process. The PG-NiONPs indicated good recyclability with high stability even after 8 adsorption cycles. Overall, the PG-NiONPs is a potential adsorbent for improved toxic dyes, metal ions and other scavengers removal from wastewater.