Arsenic Ions Research Articles

Highly selective paper-based and colorimetric detection for arsenic(V) with methylene blue-functionalized gold nanoparticles

Paper-strip-type methylene blue (MB)-functionalized gold nanoparticles (AuNPs@MB) were developed and tested as colorimetric sensors for arsenic in this study. The valence state of arsenic speciation was pH-dependent, with arsenate (As(V)) exhibiting the HAsO42– form over the pH range of 7–11. When exposed to arsenic ions, AuNPs@MB exhibited significant agglomeration between nanoparticles via an ion-pairing mechanism between MB+ and As(V), resulting in a color shift from red to blue. The amount of MB loading on the AuNPs and the pH were adjusted to optimize the colorimetric sensing efficiency. AuNPs@MB-0.9 and AuNPs@MB-1.1 were employed as colorimetric sensors at low (0–30 ppb) and high (1–100 ppb) concentrations of As(V), respectively. To confirm the feasibility of using the AuNPs@MB sensor for As(V) detection, a selectivity test was conducted in the presence of 16 cations and 5 anions. This test demonstrated the practicality of the AuNPs@MB sensor for As(V) and showed that AuNPs@MB had a very high selectivity for As(V) compared to other cations and anions. Further, a solid-state colorimetric sensor based on a cellulose paper strip was developed for arsenic detection. The results of the paper-based colorimetric sensor with AuNPs@MB were the same as those of the solution-based colorimetric sensor.

Magnesium Oxide Nanoparticles for the Adsorption of Pentavalent Arsenic from Water: Effects of Calcination.

The occurrence of heavy metal ions in water is intractable, and it has currently become a serious environmental issue to deal with. The effects of calcining magnesium oxide at 650 °C and the impacts on the adsorption of pentavalent arsenic from water are reported in this paper. The pore nature of a material has a direct impact on its ability to function as an adsorbent for its respective pollutant. Calcining magnesium oxide is not only beneficial in enhancing its purity but has also been proven to increase the pore size distribution. Magnesium oxide, as an exceptionally important inorganic material, has been widely studied in view of its unique surface properties, but the correlation between its surface structure and physicochemical performance is still scarce. In this paper, magnesium oxide nanoparticles calcined at 650 °C are assessed to remove the negatively charged arsenate ions from an aqueous solution. The increased pore size distribution was able to give an experimental maximum adsorption capacity of 115.27 mg/g with an adsorbent dosage of 0.5 g/L. Non-linear kinetics and isotherm models were studied to identify the adsorption process of ions onto the calcined nanoparticles. From the adsorption kinetics study, the non-linear pseudo-first order showed an effective adsorption mechanism, and the most suitable adsorption isotherm was the non-linear Freundlich isotherm. The resulting R2 values of other kinetic models, namely Webber-Morris and Elovich, were still below those of the non-linear pseudo-first-order model. The regeneration of magnesium oxide in the adsorption of negatively charged ions was determined by making comparisons between fresh and recycled adsorbent that has been treated with a 1 M NaOH solution.

Cd(II) and As(V) removal from the multicomponent solutions in the presence of ionic polymers using carbonaceous adsorbents obtained from herbs

Abstract Biochars and activated carbons obtained from the nettle and the sage herbs were used for Cd(II), As(V), poly(acrylic acid) and polyethylenimine simultaneous adsorption from the multicomponent aqueous solutions. Electrokinetic studies proved that both activated carbons show acidic character of the surface. The point of zero charge of the sample obtained from the nettle herb occurs at pH 3.1, whereas that of the adsorbent obtained from the sage herb at pH 4.0. Cd(II) adsorption causes the decrease in the surface charge density and the zeta potential of both activated carbons, whereas As(V) addition results in the increase of solid surface charge density and its impact on the zeta potential value depends on adsorbent type. In case of the simultaneous presence of metals and polymers, the adsorbed macromolecules have greater influence on the surface charge density and the zeta potential values than the metal ions. Cd(II) and As(V) are well adsorbed on the examined activated carbons irrespective of the solution pH (changing in the range 3–9). Maximum adsorption were 218.27 mg/g for Cd(II) and 205.53 mg/g for As(V). The polymers presence causes a decrease (80–90 %) of both metal ions adsorbed amounts, whereas the poly(acrylic acid) and polyethylenimine adsorption mechanism in the presence of cadmium and arsenic ions depends on the adsorbent type and polymer-metal interactions.

Co-transport of arsenic and micro/nano-plastics in saturated soil

Contaminants can co-exist and migrate together in the environment, causing complex (and sometimes unexpected) transport dynamics which challenge the efficient remediation of individual contaminants. The co-transport dynamics, however, remained obscure for some contaminants, such as arsenic and micro/nano-plastics (MNPs). To fill this knowledge gap, this study explored the co-transport dynamics of arsenic and MNP particles in saturated soil by combining laboratory experiments and stochastic model analysis. Isothermal adsorption and sand column transport experiments showed that the adsorption of arsenic by MNP particles followed the Freundlich model, with a maximum adsorption of 2.425 mg/g for the MNP particles with a diameter of 100 nm. In the presence of MNP particles, the efflux concentration of arsenic ions declined due to adsorption, where the decline rate decreased with the increasing MNP size and increased with the increasing adsorption capacity. Experimental results also showed that the 100 nm nano-plastic particles prohibited arsenic transport in saturated sand columns, while the 5 μm microplastics enhanced arsenic transport due to electrostatic adsorption and media pore plugging. A tempered time fractional advective-dispersion equation was then proposed to quantify the observed breakthrough curves of arsenic. The results showed that this model can reliably capture the co-transport behavior of arsenic with MNPs in the saturated soil with all coefficients of determination over 0.97, and particularly, the small MNP particles facilitated anomalous transport of arsenic. This study therefore improved the understanding and quantification of the co-transport of arsenic and MNPs in soil.

Incorporation of MgO-humic acid in iron oxide based magnetic composite facilitates for effective remediation of lead, arsenic and bacterial effect in water

Heavy metal detection and its removal from water have been a major concern for environmentalists because of its noxious effect on flora and fauna. In this study, MgO-HA@Fe3O4 has been synthesized using the co-precipitation method and employed to remove lead and arsenic from water. The adsorbent was extensively characterized using various techniques such as X-ray Diffraction (XRD), Brunauer − Emmett − Teller (BET), Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared Spectroscopy (FTIR), and Zeta Potential. Batch studies were conducted to evaluate different parameters such as pH, contact time, dose, and initial ion concentration for optimal adsorption. The data obtained from the experiments were evaluated by employing equilibrium isotherm and kinetics models. The Freundlich and second-order kinetics models were found to best describe the equilibrium and kinetic study results for Pb(II) and As(V) adsorption, respectively. The maximum adsorption capacity of MgO-HA@Fe3O4 was found to be 248.76 mg/g for lead and 104.17 mg/g for arsenic. The efficiency of the adsorbent in adsorption of heavy metal ions was tested in the presence of various co-ions such as Ca2+, Mg2+, K+, PO43−, Cl−, and HCO3–. Regeneration studies showed that the developed adsorbent had satisfactory adsorption ability even after five times regeneration cycle. Additionally, the synthesized material is capable to exhibit antibacterial properties against E. coli, indicating its potential as an effective antibacterial agent. Overall, the ease of synthesis process of the adsorbent under study, its rapid adsorption aptness, magnetic properties, and high adsorption capacity make it an ideal candidate for effectively removing lead and arsenic ions.

Iron oxide impregnated Pongamia pinnata microporous biochar composite as an effective bio-adsorbent for the remediation of arsenic ions from water

Iron oxide impregnated Pongamia pinnata microporous biochar composite as an effective bio-adsorbent for the remediation of arsenic ions from water

An ion imprinted electrochemical sensor based on flower‐like gold nanoparticles for the detection of trace arsenic(III) ions in water and food samples

AbstractA selective and sensitive electrode based on Au−S bonds between As(III) ion‐imprinted polymer (IIP) and the flower‐like gold nanoparticles (FL‐AuNPs) had been rationally developed for detecting As(III) by using the square wave voltammetry (SWV) method. Under optimized measurement conditions, the prepared electrochemical sensor exhibited obvious detection performance of As(III) in the range of 0.009 μg/L–0.50 μg/L with a relatively low detection limit of 0.015 μg/L. Furthermore, the imprinted electrochemical sensor displayed good reusability, excellent specificity, and demonstrated high potential for environmental control with a recovery rate between 80.7 % and 113.3 %.

A Novel Fluorescent Aptasensor for Arsenic(III) Detection Based on a Triple-Helix Molecular Switch.

A novel aptamer-based fluorescent-sensing platform with a triple-helix molecular switch (THMS) was proposed as a switch for detecting the arsenic(III) ion. The triple helix structure was prepared by binding a signal transduction probe and arsenic aptamer. Additionally, the signal transduction probe labeled with fluorophore (FAM) and quencher (BHQ1) was employed as a signal indicator. The proposed aptasensor is rapid, simple and sensitive, with a limit of detection of 69.95 nM. The decrease in peak fluorescence intensity shows a linear dependence, with the concentration of As(III) in the range of 0.1 µM to 2.5 µM. The whole detection process takes 30 min. Moreover, the THMS-based aptasensor was also successfully used to detect As(III) in a real sample of Huangpu River water with good recoveries. The aptamer-based THMS also presents distinct advantages in stability and selectivity. The proposed strategy developed herein can be extensively applied in the field of food inspection.

The elimination of arsenic from natural gas condensate via pulse sieve-plate column: Experimental and application of DFT for chemical structure

This work focuses on the elimination of arsenic ions from natural gas condensate via pulse sieve-plate column. The extraction of arsenic ions using the extractants: hydrochloric acid (HCl), Methanol (MeOH) and HCl/MeOH are investigated via density functional theory (DFT). The DFT method clearly demonstrates the synergistic reaction mechanism of the extractant HCl/MeOH, providing an improved extraction effect greater than the use of single extractants. Applying optimal conditions: MeOH (5 M), HCl (1 M), feed flowrate (55 ml/min), extractant flowrate (220 ml/min) and pulse velocity (2 cm/s), it is found that the pulse sieve-plate column leads to an increase in extraction of triphenylarsine. Mass-transfer parameters, including the Sauter mean diameter: 1.917 mm, the axial dispersion coefficient of the continuous phase: 0.012 m2/s, the extract percentage: 94.55%, the overall mass transfer coefficient: 1.228x10-3 s−1 as well as height of a transfer unit (HTU): 22.92 cm are also calculated under optimal conditions.

Adsorption removal of arsenic from Aqueous solution by carboxy methyl Cellulose(CMC) modified with montmorillonite

In this research, CMC/MMT nano composite was prepared using the free radical polymerization method and evaluated as Arsenic ions removal adsorption from an aqueous solution. We used the Design expert (CCD) to remove Arsenic Ions optimally. SEM, XRD and FTIR analyses were used to determine the adsorbent properties. The experimental design was done with four time variables (25–40min), Arsenic concentration (0.5–2 ppm), adsorbent dose (0.05-2gr) and pH (4–8). The interaction and combined effects of the variables were evaluated by the analysis of variance (ANOVA) table. A quadratic polynomial regression equation was developed to predict the response under optimal conditions. The results of kinetic studies and adsorption isotherms present that the kinetics of Arsenic ion adsorption by CMS/MMT adsorbent follows the quadratic equation and the Langmuir isotherm with a better correlation coefficient than the Freundlich equation. Furthermore, under optimal conditions (pH = 5.6, t = 34 min), 1.9 ppm Arsenic is adsorbed per 0.09 g of the adsorbent with 85% efficiency which indicates that the carboxymethyl cellulose hydrogel modified with Montmorillonite is a suitable adsorbent to remove Arsenic ions from aqueous solution.

Preparation of novel Polyvinylidene fluoride/boehmite composite membrane made using nonsolvent induced phase separation method for arsenate ion removal from water

AbstractPolyvinylidene fluoride/boehmite composite membranes with hydrophilic surfaces were prepared using the nonsolvent induced phase inversion technique (NIPS) method to remove arsenate ions from water. The nanoparticles were added with different boehmite filler content. The contact angle of the bare membrane is 850, and it is reduced to 530, imparting hydrophilicity due to the presence of boehmite nanoparticles. The mechanical characteristics of the membranes have significantly improved. The BET and SEM results have shown that the average pore diameter gets reduced with boehmite addition, and surface area increases. Additionally, the use of nanoparticles enhanced the membranes' thermal stability. The nanofiltration unit is used to filter the arsenic‐contaminated water. The transmembrane pressure of ~4 bar is applied to all the membranes, and arsenic rejection; the flux of the membranes was calculated. The membrane has shown the highest rejection of 55% with a flux of 3.5659 L/m2.h.

Fabrication and characterization of MXene/carbon composite-based nanofibers (MXene/CNFs) membrane: An efficient adsorbent material for removal of Pb+2 and As+3 ions from water

High contamination of toxic heavy metals such as lead (Pb2+) and arsenic (As3+) in water is a major threat to human health and aquatic life. Recently, MXene has been applied as a promising platform for the adsorption of heavy metals. However, its composites have rarely been investigated for the removal of heavy metals yet. Herein, we have synthesized MXene/Carbon composite-based nanofibers (MXene/CNFs) membrane for efficient removal of Pb2+ and As3+ ions up to their permissible limits through an efficient adsorption study. The adsorption results were fit well with both the Langmuir and the pseudo-second-order models. The MXene/CNFs composite membrane showed high adsorption capability for Pb2+ (12.5 mg.g-1) and As3+ (3.3 mg.g-1) at an optimized neutral pH within 20 and 30 min respectively. The removal rates for Pb2+ and As3+ ions were achieved at 89% and 81% respectively which are much sufficient to treat contaminated water at low concentrations (10 µgL-1 to 10 mgL-1). Additionally, the MXene/CNFs composite membrane showed good recycling up to 4 cycles with removal efficiencies of both ions Pb2+ (77%) and As3+ (60%). As a result, the prepared MXene/CNFs membrane pave the way for an efficient, affordable, lightweight, and environmentally friendly route for the removal of lead and arsenic ions up to their permissible limit for drinking water.

Characterization of the Incorporation and Adsorption of Arsenate and Phosphate Ions into Iron Oxides in Aqueous Solutions

This article provides an overview of the incorporation and adsorption of arsenate and phosphate into iron oxides formed in aqueous solutions. Although arsenic (As) and phosphorus (P) and belong to the same group in the periodic table, As is usually toxic, whereas P is a biological element. Arsenate and phosphate ions can be incorporated into iron oxides through different routes, depending on the solution conditions. In aqueous solutions, the chemical state of Fe in iron oxides is FeII (ferrous) or FeIII (ferric), that of As is AsIII (arsenite) and AsV (arsenate), and that of phosphorus is PV (phosphate). The composition and structure of iron oxides, including ferric oxyhydroxides and hydroxides formed in aqueous solutions, are affected by solution conditions such as the electrochemical potential, pH, temperature, and the chemical state and composition of the relevant elements. Moreover, arsenate and phosphate ions are usually adsorbed on the surface of iron oxides in aqueous solutions, but the incorporation and adsorption of arsenate and phosphate ions in iron oxides cannot be easily explained using simple thermodynamic models. This is because these characteristics are accompanied by different stages of coprecipitation, incongruent dissolution of multicomponent iron oxides, and so on. Since hydrated iron-oxide particles are often very fine and poorly crystallized, they are difficult to filter. However, it has been shown that coarse polyhedral particles of hydrated iron oxide can be synthesized by oxidizing FeII ions. In addition, the coarse particles of hydrated iron oxide are transformed into agglomerates of fine FeIII oxides with a coarse outer shell by alkaline treatment, and these coarse porous iron-oxide particles exhibit good anion-adsorption capacity in aqueous solutions. The formation mechanisms of these different iron-oxide particles are discussed based on the results of the incorporation and adsorption of arsenate and phosphate ions in iron oxides in aqueous solutions.

Adsorptive removal of arsenic ions from contaminated water using low-cost schwertmannites and akaganéites

Schwertmannite and akaganéite have potential in treatment of arsenic contaminated waters. In this work, schwertmannite and akaganéite were synthesized by chemical and biological methods. Characterization and analysis results showed about 120 m2/g for schwertmannite spheres with a diameter of 2–5 μm (Sch-Chem) and about 0.5 μm (Sch-Bio) and 240–280 m2/g for akaganéite rod with a length of about 300–500 nm (Aka-Chem) and 150 nm (Aka-Bio). Agglomerated particle average diameters (μm) of synthesized products in solutions were 32.5, 20.6, 0.480 and 26.4, respectively. Schwertmannite and akaganéite were used to investigate arsenic adsorption behaviors in aqueous solutions by batch experiments, under various reaction times, initial arsenic and adsorbent levels, pH values, and anions (Cl−, NO3−, H2PO4−, CO32−, and SO42−). Adsorption data well fitted to pseudo-second-order rate model (R2 = 0.999), and Langmuir (R2 = 0.977–0.998) and Freundlich (R2 = 0.948–0.998) isothermal models at pH 7.0. Maximum adsorption capacities of As(III)/As(V) were 102/98.3, 110/115, 6.40/7.03 and 30.3/34.8 mg/g, respectively. Anions of SO42− and H2PO4− can affect arsenic removal efficiency. Adsorbents with pHZPC of 4.0–5.0 still had a good arsenic removal ability at pH 3.0–9.0, due to a main adsorption mechanism of anionic exchange between hydroxyl group (or sulfate) and arsenic ions. Further, schwertmannite candidates were used in arsenic removal from polluted groundwater. Breakthrough points (bed volume, mL) for Sch-Bio/Sch-Chem were about at 90/120, 70/(100–110) and 80/110 for As(III), As(V), and total As, respectively. It demonstrated that akaganéite and schwertmannite could be potentially applied in treatments of arsenic-polluted waters.

Nanoscale characterization of the sequestration and transformation of silver and arsenic in soil organic matter using atom probe tomography and transmission electron microscopy.

This study investigates the sequestration and transformation of silver (Ag) and arsenic (As) ions in soil organic matter (OM) at the nanoscale using the combination of atom probe tomography (APT), transmission electron microscopy (TEM), focused ion beam (FIB), ion mill thinning and scanning electron microscopy (SEM). Silver-arsenic contaminated organic-rich soils were collected along the shore of Cobalt Lake, a former mining and milling site of the famous Ag deposits at Cobalt, Ontario, Canada. SEM examinations show that particulate organic matter (OM grains) contains mineral inclusions composed of mainly Fe, S, and Si with minor As and traces of Ag. Four OM grains with detectable concentrations of Ag (by SEM-EDS) were further characterized with either a combination of TEM and APT or TEM alone. These examinations show that As is predominantly sequestered by OM through either co-precipitation with Fe-(hydr)oxide inclusions or adsorption on Fe-(hydr)oxides and their subsequent transformation into scorodite (FeAsO4·2H2O)/amorphous Fe-arsenate (AFA). Silver nanoparticles (NPs) with diameters in the range of ∼5-20 nm occur in the organic matrix as well as on the surface of Fe-rich inclusions (Fe-hydroxides, Fe-arsenates, Fe-sulfides), whereas Ag sulfide NPs were only observed on the surfaces of the Fe-rich inclusions. Rims of Ag-sulfides on Ag NPs (TEM data), accumulation of S atoms within and around Ag NPs (APT data), and the occurrence of dendritic as well as euhedral acanthite NPs with diameters in the range of ∼100-400 nm (TEM data) indicate that the sulfidation of the Ag NPs occurred via a mineral-replacement reaction (rims) or a complete dissolution of the Ag NPs, the subsequent precipitation of acanthite NPs and their aggregation (dendrites) and Ostwald ripening (euhedral crystals). These results show the importance of OM and, specifically the mineral inclusions in the sequestration of Ag and As to less bioavailable forms such as acanthite and scorodite, respectively.

Quantifying arsenic and mercury in aqueous media via bio-inspired gold nanoparticles modified by mango leaf extract.

The present study conveys a new method for detecting arsenic(iii) and mercury(ii) in aqueous solution via bio-inspired gold nanoparticles. The process of synthesizing gold nanoparticles involves the utilization of the chemical reduction method. The functionalization of gold nanoparticles' surface is achieved via mango leaf extract. The as-synthesized nanoparticles are characterized by UV-Vis and DLS which reveal a plasmonic peak around ∼520 nm with an average size distribution of ∼44 nm. The modified gold nanoparticles have demonstrated selective detection capabilities towards arsenic(iii) as well as mercury(ii), as evidenced by color changes observed in the presence of ions of arsenic as well as mercury. The addition of mercury and arsenic lead to the overall aggregation-thereby bringing a colorimetric response. The limit of detection was determined to be 1 ppb and 1.5 ppb for arsenic(iii) and mercury(ii) ions, respectively along with exceptional linearity.

Adsorption of Arsenic, Lead, Cadmium, and Chromium Ions from Aqueous Solution Using a Protonated Chabazite: Preparation, Characterization, and Removal Mechanism

The adsorption of As(V), Pb(II), Cd(II), and Cr(III) ions from aqueous solutions on natural and modified chabazite was studied. The functionalization of chabazite was performed via a protonation and calcination with the aim of generating Lewis acid sites to improve its anion exchange properties. The surface and physicochemical properties of both adsorbents were studied and compared. The adsorption isotherms of tested heavy metal ions were quantified and modeled to identify the best isotherm equation. Steric parameters for the adsorption of these ions were also calculated with a monolayer statistical physics model. Natural chabazite showed the maximum adsorption capacity for Pb(II), while the modified zeolite improved its As(V) properties in 79%. These results showed that the modified zeolite was able to remove both cations and anions from aqueous solution. The application of this functionalized chabazite can be extended for the removal of other anionic pollutants from water, thus opening the possibility of preparing new adsorbents with tailored properties for water treatment.

Thick-walled coating in Gunn diode for measuring of electromagnetic radiation power in microwave range

In the introduction, the analysis of the physical basis for the operation of the semiconductor Gunn diode is carried out and the issues that should be resolved in substantiation of the basic physical principles of this diode operation are stated. At applied voltages of up to 0.6 V to a gallium arsenide or indium phosphide Gunn diode, free electrons appear in the conduction band of aluminum as a result of ionization of negative ions of gallium or indium atoms. At voltages from 0.6 to 2.0 V, free electrons appear in the aluminum conduction band as a result of ionization of negative ions of arsenic atoms, and at voltages from 0.6 to 3.0 V — phosphorus. The formation of negative gallium or indium ions is caused by electron capture directly from the aluminum base, while the formation of negative arsenic or phosphorus ions is mainly due to spontaneous electron transfer from the aluminum conduction band and from the negative gallium or indium ions. Electric current flows only over the surface of a gallium arsenide or indium phosphide crystal. The frequency of electric current oscillation is defined by the voltage applied to the Gunn diode and the thickness of the gallium arsenide or indium phosphide crystal. Determination of the power of microwave signals by the Gunn diode is carried out by applying a constant voltage between the cathode and the anode, which provides the frequency of current oscillation equal to the frequency of the measured microwave signal. The maximum radiation power in microwave wavelengths measured by the Gunn diode is determined by the equality of the electromagnetic wave perturbation energy and the electron affinity energy of gallium or indium atoms in the vicinity of the aluminum conduction band.

A Brief Review of Recent Results in Arsenic Adsorption Process from Aquatic Environments by Metal-Organic Frameworks: Classification Based on Kinetics, Isotherms and Thermodynamics Behaviors.

In nature, arsenic, a metalloid found in soil, is one of the most dangerous elements that can be combined with heavy metals. Industrial wastewater containing heavy metals is considered one of the most dangerous environmental pollutants, especially for microorganisms and human health. An overabundance of heavy metals primarily leads to disturbances in the fundamental reactions and synthesis of essential macromolecules in living organisms. Among these contaminants, the presence of arsenic in the aquatic environment has always been a global concern. As (V) and As (III) are the two most common oxidation states of inorganic arsenic ions. This research concentrates on the kinetics, isotherms, and thermodynamics of metal-organic frameworks (MOFs), which have been applied for arsenic ions uptake from aqueous solutions. This review provides an overview of the current capabilities and properties of MOFs used for arsenic removal, focusing on its kinetics and isotherms of adsorption, as well as its thermodynamic behavior in water and wastewater.

Application of sulphate and magnesium enriched waste rapeseed cake biochar for recovery of Cu(II) and Zn(II) from industrial wastewater generated in sulphuric acid plants

The development of an efficient and green adsorbent is of great significance for copper(II) and zinc(II) removal and recovery from industrial wastewater. In this study, for the first time, waste rapeseed cake is used as a biosource to synthesize MgO-SO3 enriched biochar. The newly developed adsorbent was produced in a one-step process by pyrolysis at 973.15 K for 2 h, under anoxic conditions. Porous structure, specific surface area, and composition of biochar were studied. Furthermore, sorption properties of the obtained biochar in relation to copper(II), zinc(II), and arsenic(III) ions were also studied. The impact of parameters such as: sorption time, temperature, adsorbate concentration, sorbent mass, and solution pH on the efficiency of the adsorption process of the studied cations was examined. Rapeseed cake biochar exhibits good Cu(II) adsorption capacity (90.4 mg g−1) with a short equilibrium time (4 h), which indicates the competitiveness to similar adsorbents. The adsorption of Cu(II) on the biochar was more consistent with the pseudo-second-order kinetic models and Langmuir model. The Freundlich and pseudo-second-order kinetic models best fitted the removal of Zn(II) by modified biochar. The mechanism of Cu(II) and Zn(II) adsorption was also postulated. Experimental data collected have shown that the presence of arsenic(III) at higher concentrations adversely affects the sorption efficiency of Cu(II) and Zn(II) ions. Thus, this study shows that the sorbent can be successfully used for the separation of Cu(II) and Zn(II) from technological wastewaters. A flowsheet for the proposed process is presented.