Treatment of metal-contaminated wastewater: a comparison of low-cost biosorbents

A comprehensive review of heavy metals (Pb2+, Cd2+, Ni2+) removal from wastewater using low-cost adsorbents and possible revalorisation of spent adsorbents in blood fingerprint application

An increasing amount of water pollution is being caused by an increase in industrial activity. Recently, a wide range of methods, including extraction, chemical coagulation, membrane separation, chemical precipitation, adsorption, and ion exchange, have been used to remove heavy metals from aqueous solutions. The adsorption technique is believed to be the most highly effective method for eliminating heavy metals from wastewater among all of them. However, it generates secondary waste that can pose a risk to the environment. Agricultural waste has potential to be collected and converted into carbon nanomaterials, then coated with metal oxides for the removal of Pb2+, Cd2+, and Ni2+ ions and then the reuse of heavy metal spent adsorbents in blood fingerprint detection (BFP) can be studied. This review highlights the eco-friendly nature and abundant availability of these materials while advocating for their integration into mainstream wastewater treatment practices. It explores the prospect of revalorizing spent adsorbents in blood fingerprint applications, demonstrating a dual-purpose utilisation that bridges environmental remediation with advancements forensic sciences. Different method of removal of Pb2+, Cd2+ and Ni2+, removal technique as well as other reuse applications of spent adsorbents are also discussed.

Multi-Element Fingerprinting Combined with Chemometrics for Identification of Seaweeds and Innovative Risk-Benefit Assessment

Seaweeds are one of the major marine foods with high values. The diversity of seaweed species significantly impacts their quality and is closely linked to their purity and safety. For the first time, this study established a model to discriminate seaweed species using a multi-element fingerprinting approach for species identification. Twenty-nine elements derived from seaweeds were analyzed. Chemometrics showed that seaweed samples could be well separated by the established multi-element fingerprints, of which Ag, Mn, Sr, and K were the most important variables for discrimination. Furthermore, the present study proposed an innovative risk-benefit assessment strategy for seaweeds that considers both risks and benefits, developing a novel risk-benefit assessment model from both dietary and medicinal perspectives for the first time. Our innovative strategy was well-conceived to accurately and effectively differentiate seaweeds based on species and scientifically evaluate both benefits and risks associated with seaweeds. This strategy is poised to offer invaluable insights into the sustainable growth of the seaweed sector and to bolster public health initiatives, ensuring a robust and forward-looking approach to both industry and healthcare advancements.

Application of Noug (Guizotia abyssinica cass.) stalk activated carbon for the removal of lead (II) ions from aqueous solutions

Due to the rise of industries worldwide, huge amounts of pollutants including heavy metals are released into the surroundings. Disposal of effluents containing heavy metals in higher concentrations without proper treatment is common in industries; lead is one of them. This study aims to determine and optimize the efficiency of Noug (Guizotia abyssinica Cass.) stalk porous carbon (NSAC) for the elimination of lead (II) from aqueous solutions. For studying the adsorption characteristics of Noug stalk activated carbon (NSAC) an adsorbate of lead (II) ions was used. The interaction and effect of the following parameters on Pb(II) adsorption were investigated using Design Expert version 7.0 software (central composite design) to determine the optimum adsorption condition: pH, initial concentration of Pb(II) ion, adsorbent dose, and contact time. The optimized condition for the elimination of lead (II) using Noug stalk porous carbon (98.77 %) was achieved at pH [4.87], initial concentration of Pb(II) [84.66 mg/L], adsorbent dose [18.43 g/L], and contact time [2.04 h]. The pseudo-second-order kinetics and the Langmuir isotherm model which had a maximum adsorption capacity of 89.25 mg/g, provided the best-fit models for Pb(II) adsorption, with R2 values of 0.99 and 0.98, respectively. Efficient elimination of Pb(II) from wastewater can be performed through the use of NSAC. Future research should delve more into column adsorption under continuous wastewater flow.

Comprehensive assessment of carbon-, biomaterial- and inorganic-based adsorbents for the removal of the most hazardous heavy metal ions from wastewater

Owing to the high cost of recycling waste, underdeveloped countries discharge industrial, agricultural, and anthropogenic effluents without pretreatment. As a result, pollutant-loaded waste enters water bodies. Among the diverse toxic contaminants, heavy metal ions are the most detrimental because of their chronic toxicity, non-degradability, prevalence, and bioaccumulation. The growing shortage of water resources demands the removal of heavy metal ions from wastewater. Three SDGs of the sustainability agenda of the United Nations appeal for clean water to protect life beneath water and on land depending on the water sources. Therefore, efficient environmentally friendly approaches for wastewater treatment are urgently required. In this regard, several methods have been developed for the removal of heavy metal ions from wastewater, including adsorption as the most widely used method owing to its eco-friendly, cost-effective, and sustainable nature. The present review discusses the progress in the preparation and application of various adsorbents based on carbon, micro-organisms, agricultural waste and inorganic materials for the extraction of toxic metal ions such as Pb2+, Cr6+, As3+, As5+, Hg2+ and Cd2+. Herein, we provide information on the role of the homogeneity and heterogeneity of adsorbents, kinetics of the adsorption of an adsorbate on the surface of an adsorbent, insights into adsorption reaction pathways, the mechanism of the sorption process, and the uptake of solutes from solution. The present review will be useful for researchers working on environmental protection and clean environment.

Modeling Cu removal from aqueous solution using sawdust based on response surface methodology

Copper (Cu), as one of the heavy metals widely used in industrial and agricultural activities, has a fundamental role in the pollution of water resources. Therefore, removing Cu from the aqueous solutions is considered an important challenge in the purification of water resources. Thus, in this study, sawdust with a diameter of 260-600 μm was used to remove Cu from the aqueous solutions. At first, sawdust was washed using distilled water and dried at laboratory temperature. Cu absorption experiments in closed conditions were performed based on the central composite design (CCD) model and with a range of initial Cu concentrations equal to 1-25 mgl-1. The amount of changes for other variables, including pH, time, and amount of sawdust, was equal to 2-10, 5-185 (min), and 5-25 (gl-1), respectively. After the completion of each test, the remaining Cu concentration in the solution was measured using atomic absorption, and the percentage of Cu removed was determined from the difference between the initial and final concentrations. The results showed that the CCD model has a favorable ability to predict Cu removal from the aqueous solutions (R2=0.90 and RSME=3.34%). Based on the Pareto analysis, contact time, the amount of sawdust, pH, and the Cu concentration had the most significant effect on removing Cu from the solution. Contact time, amount of sawdust, and pH were directly related, and the amount of dissolved Cu was proportional to the removal of Cu from the solution. Therefore, sawdust is desirable as a natural adsorbent, and the removal efficiency of Cu from solutions with low Cu concentration is very high (94%). In this regard, it is advised to use sawdust in the process of targeting Cu and heavy metals due to its low cost and availability.

Optimal synthesis of dolochar derived faujasite zeolite X for highly effective Cd(II) removal

Cadmium-induced water pollution is a major environmental issue because of its persistent nature and adverse ecological impacts. Adsorption is a highly favored method due to its versatility and high efficacy in cadmium removal. Hence, the present work aims to develop a low-cost, highly effective adsorbent-dolochar-derived nanoporous zeolite to easily and effectively purify Cd(II) polluted water. The work focuses on the Cd(II) batch adsorption study using the optimal hydrothermal synthesis of a crystalline faujasite Zeolite X (ZX) from dolochar. The synthesis parameters were optimized using Response Surface Methodology, specifically Box Behnken Design (RSM-BBD), to maximize the crystallinity percentage. Variables such as initial Cd(II) concentration, solution pH, dosage, time, and temperature were studied for the Cd(II) batch adsorption study. The optimum conditions for synthesizing ZX include NaOH/Dolochar, crystallization temperature, and crystallization time of 1.375, 100 °C, and 11 h, respectively. The resultant XRD structure exhibited an average crystal size and crystallinity of 0.79 μm and 87.231 %, respectively. The average pore size, micropore volume, micropore area, and total surface area were 3.316 nm, 0.311 cc. g-1, 567.226 m2 g-1, and 583.117 m2 g-1, respectively. The maximum removal was accomplished with optimum conditions of 0.25 g.L-1 dosage, 80 min, at 313.15 K, and 6.5 pH. Adsorption isotherm results agreed with those hypothesized by Freundlich isotherm, with a maximum adsorption capacity of 714.285 mg g-1, and the pseudo-second-order kinetic model describes the adsorption kinetics well. The relevance of the results highlights the importance of using this dolochar-derived nanoporous zeolite as an adsorbent to effectively treat Cd(II) containing wastewater.

Dielectrophoresis-assisted removal of Cd and Cu heavy metal ions by using Chlorella microalgae

A novel dielectrophoresis (DEP)-assisted device for the bioremediation of heavy metal ions by using Chlorella microalgae is presented in this paper. To generate the DEP forces, pairs of electrode mesh were inserted in the DEP-assisted device. By applying DC electric field via the electrodes, the inhomogeneous electric field gradient is induced and the strongest non-uniform electric field exists near the mesh cross-corner. After the adsorption of Cd and Cu heavy metal ions by Chlorella, the Chlorella chain were trapped along the vicinity of the electrode mesh. Then, the effects of Chlorella concentration on the adsorption of heavy metal ions, and the applied voltage and electrode mesh size on the removal of Chlorella are conducted. In the co-existing Cd and Cu solutions, the individual adsorption ratio of Cd and Cu reaches as high as approximately 96% and 98%, respectively, showing excellent bioremediation capability of multiple heavy metal ions in wastewater. By adjusting the applied electric voltage and the mesh size, the Chlorella adsorbed with Cd and Cu are captured by negative DC-DEP effects and the removal ratio of Chlorella reach an average of 97%, providing a method for the removal of multiple heavy metal ions in wastewater by using Chlorella microalgae.

Determination of Phenol with Peroxidase Immobilized on CaCO3

Phenols are widely used in industries despite their toxicity, which requires governments to limit their concentration in water to 5 mg/L before discharge to the city sewer. Thus, it is essential to develop a rapid, simple, and low-cost detection method for phenol. This study explored two pathways of peroxidase immobilization to develop a phenol detection system: peroxidase encapsulation into polyelectrolyte microcapsules and peroxidase captured by CaCO3. The encapsulation of peroxidase decreased enzyme activity by 96%; thus, this method cannot be used for detection systems. The capturing process of peroxidase by CaCO3 microspherulites did not affect the maximum reaction rate and the Michaelis constant of peroxidase. The native peroxidase—Vmax = 109 µM/min, Km = 994 µM; CaCO3–peroxidase—Vmax = 93.5 µM/min, Km = 956 µM. Ultimately, a reusable phenol detection system based on CaCO3 microparticles with immobilized peroxidase was developed, capable of detecting phenol in the range of 700 ng/mL to 14 µg/mL, with an error not exceeding 5%, and having a relatively low cost and production time. The efficiency of the system was confirmed by determining the content of phenol in a paintwork product.

Removal of toxic lead from aqueous solution using a low-cost adsorbent

Valorization of waste materials and byproducts as adsorbents is a sustainable approach for water treatment systems. Pottery Granules (PG) without any chemical and thermal modification were used as a low-cost, abundant, and environmentally benign adsorbent against Pb(II), the toxic metal in drinking water. The porous structure and complex mineral composition of PG made it an efficient adsorbent material for Pb(II). The effect of key physicochemical factors was investigated to determine the significance of contact time, PG dose, pH, solution temperature, and coexisting ions, on the process. Pb(II) removal increased by PG dose in the range of 5-15 g/L, and agitation time from 5 to 60 min. Increasing Pb(II) concentration led to a drop in Pb(II) removal, however, adsorption capacity increased significantly as concentration elevated. Pb(II) removal also increased significantly from ~ 45% to ~ 97% by pH from 2 to 12. A ~ 20% improvement in Pb(II) adsorption after rising the solution temperature by 30˚C, indicated the endothermic nature of the process. The sorption was described to be a favorable process in which Pb(II) was adsorbed in a multilayer onto the heterogeneous PG surface. The qmax of 9.47 mg/g obtained by the Langmuir model was superior among many reported low-cost adsorbents. The Pb(II) adsorption was described well by the Pseudo- first-order kinetic model. Na⁺, Mg²⁺, Ca²⁺, Cd²⁺, and Zn²⁺ showed a negligible effect on Pb(II) adsorption. However, the presence of Mn²⁺ and Fe²⁺ significantly hindered the process efficacy. In conclusion, the use of waste material such as PG against Pb(II) is a viable option from the economic and effectiveness points of view.

Adsorption of lead, copper and zinc in a multi-metal aqueous solution by waste rubber tires for the design of single batch adsorber

Heavy metal pollution has emerged as one of the most serious environmental challenges facing the world today. The removal of heavy metals from the effluent is of special environmental concern because of their toxicity and persistence in nature. This study presents the suitability of activated carbon from waste rubber tire as a low-cost adsorbent for multiple adsorption of copper, lead and zinc from wastewater. The adsorbent removed heavy metal ions effectively from solution medium in the order of copper > lead > Zinc. The adsorption process was rapid with all metals reaching equilibrium within 120 min. The optimum pH for Lead was achieved at 5 and 6 for copper and Zinc. The removal of heavy metals was discovered to increase with adsorbent dosage and contact time and reduced with initial concentration. The adsorption of multiple heavy metals was modeled using Freundlich and Langmuir adsorption isotherms to assess the experimental findings. The equilibrium data better fitted to the Langmuir isotherm with regression coefficient (R2) of 0.9831, 0.9992 and 0.9953 for lead, copper and zinc respectively. The maximum adsorption capacities (Qmax) at equilibrium were 9.6805 mg/g, 12.4378 mg/g and 4.9950 mg/g for Lead, Copper and Zinc respectively. The adsorption kinetics indicated that pseudo-second-order kinetic model described well the sorption mechanism for multiple adsorption of heavy metals with R2 of more than 0.99 for all metal ions. An empirical model for predicting and designing of a single batch adsorber for 95 % multiple heavy metal ion removal at any given initial heavy metal ion concentration and effluent volume was further developed using activated carbon from waste rubber tires. Waste rubber tire Activated carbon demonstrated an ability for the treatment of wastewater containing these heavy metals in multimetal solutions.

Sustainable management of cut flowers waste by activation and its application in wastewater treatment technology

Cut flowers and floral waste (CFW) is a major concern in the present era. This study emphasizes the reuse of cut flowers as a neat bioadsorbent and activated carbon (AC). The biomass from the cut flowers was utilized as a neat bioadsorbent for the removal of the antibiotic levofloxacin and lead ions from water. The results revealed that the neat bioadsorbent was able to remove 60% levofloxacin and 45% of lead ions. Upon chemical activation of the CFW (using KOH), almost all levofloxacin and more than 99% of lead ions were removed. Physical activation (using CO₂) gave a material that removed 90% of levofloxacin and 85% of lead ions. The adsorption of levofloxacin and lead ions on all the adsorbents followed Langmuir isotherms and pseudo-second-order kinetic model. The results have been further explained via the prediction of interaction energies between the adsorbates and adsorbents using COSMO-RS simulation.

Closing the loop in a constructed wetland for the improvement of metal removal: the use of Phragmites australis biomass harvested from the system as biosorbent

Among the numerous clean-up techniques for water treatment, sorption methods are widely used for the removal of trace metals. Phragmites australis is a macrophyte commonly used in constructed wetlands for water purification, and in the last decades, its use as biosorbent has attracted increasing attention. In view of a circularly economy approach, this study investigated improvement of trace metal removal by recycling the biomass of P. australis colonizing a constructed wetland, which operates as post-treatment of effluent wastewater from an activated sludge plant serving the textile industrial district of Prato (Italy). After the annual mowing of the reed plants, the biomass was dried and blended to derive a sustainable and eco-friendly biosorbent and its sorption capacity for Fe, Cu, and Zn was investigated comparing the batch system with the easier-to-handle column technique. The possibility of regeneration and reuse of the biosorbent was also evaluated. The biomaterial showed an interesting sorption capacity for Cu, Fe, and Zn, both in batch and in column experiments, especially for Fe ions. The immobilization of the biosorbent in column filters induced some improvement in the removal efficiency, and, in addition, this operation mode has the advantage of being much more suitable for practical applications than the batch process.

White Eggshells: A Potential Biowaste Material for Synergetic Adsorption and Naked-Eye Colorimetric Detection of Heavy Metal Ions from Aqueous Solution

In the present work, we have utilized a simple, no-cost, unmodified eggshell powder as a naked-eye colorimetric detector, which on simple dispersion in aqueous solution of metal ions exhibited characteristic color change from white to pale green, pale blue, yellow, pale yellow, dark yellow, pale pink, blue, and brown for metal ions V⁴⁺, Cr³⁺, Cr⁶⁺, Fe²⁺, Fe³⁺, Co²⁺, Cu²⁺, and Ag⁺, respectively. The effects of various parameters like concentration of metal ions, pH, temperature, and adsorbent dosage were investigated by batch sorption experiments. Also, Freundlich and Langmuir models were used to describe the adsorption isotherm. The eggshell powder before and after adsorption was characterized qualitatively by the naked-eye and quantitatively by diffuse reflectance spectroscopy-UV, Fourier transform infrared, atomic absorption spectroscopy, powder X-ray diffraction, scanning electron microscopy with energy-dispersive X-ray spectroscopy, Brunauer-Emmett-Teller, zeta potential, and X-ray photoelectron spectroscopy techniques. In addition, the competitive adsorption of metal ions in mixtures and the recycle experiments were carried out to prove the sustainability of the material. Further, the red, green, and blue alterations were extracted from the colorimetric array and subjected to hierarchical clustering analysis using the Ward method by calculating the Euclidean distance, which displayed facile discrimination of 10 heavy metal ions at 1 mM level. Thus, the unmodified eggshell powder has been proven to be an impressive value-added sustainable material for synergistic metal adsorption and colorimetric naked-eye detection of a series of metal ions with detection limits of 10^-4 M for Fe³⁺, Fe²⁺, and Cu²⁺; 10^-3 M for Cr³⁺, Cr⁶⁺, Ag⁺, and Co²⁺; and 5 × 10^-3 M for V⁴⁺.

Synthesis and Characterisation of Nano-Biosorbents and Their Applications for Waste Water Treatment

Nanotechnology is one of the most reliable techniques for the remediation of heavy metals. As nanoparticles have a higher surface area to volume, ratio, and high surface energies, so nano-based absorbents are very efficient. Adsorption technique is the most preferred for the remediation of wastewater pollutants. In the current study, a comparative study was done between bio sorbents, nanosorbents and bio nanosorbents. The chapter studies with the synthesis and characterization of the bio sorbents, bionanosorbents, their mechanism of sorption, their synthesis, in addition, application for the remediation of heavy metals from wastewater. The fly ash is an industrial byproduct. Biosorbents have immense applications in the field of bioremediation of heavy metals. Further, their components have also enhanced removal efficiency from the wastewater.

Treatment of high-nitrate wastewater mixtures from MnO2 industry by Chlorella vulgaris

The aim of this work was to study the biotreatment of mixed wastewaters collected from two points of MnO₂ industry by Chlorella vulgaris. Their growth rates in four mixed wastewaters with mass ratio of wastewater 1^#:2^# of 20:1, 50:1, 100:1, and 200:1 were characterized, and the lag phase was shortened with increase of nitrate concentrations. The N, P, and metal removal kinetics were quantified each other day to evaluate the bio-treatment efficiencies of high-nitrate wastewaters from MnO₂ industry. 84.68% and 98% of N, P has been removed. The Ca, Zn, Mn, and Si in mixed wastewaters was removed with maximum removal efficiencies of 97.91%, 99.37%, 99.44%, and 81.68%, respectively. The compositions of Chlorella vulgaris cultured in mixed wastewaters, including proteins, lipids, ash contents, and carbohydrates, were investigated in detail. The optimum HHV of Chlorella vulgaris about 18 MJ/Kg presented a potential to decrease the cost of algal biofuel.

A Comparative Sorption Study of Ni (II) form Aqueous Solution Using Silica Gel, Amberlite IR-120 and Sawdust

The presence of heavy metals in water causes serious problems and their treatment before incorporating into the water body is a challenge for researchers. The present study was conducted to compare the sorption study of Ni (II) using silica gel, amberlite IR-120 and sawdust of mulberry wood in batch system under the influence of pH, initial Ni (II) concentration and contact time. It was observed that sorption process was depending upon pH and maximum sorption was achieved at pH 7.0. Kinetic data were well fitted into pseudo-second order kinetic model due to high R2 values and closeness of experimental sorption capacity and calculated sorption capacity of pseudo-second order. Isotherms study showed that Langmuir is one of the most suitable choices to explain sorption data due to high R2 values. The monolayer sorption capacities of silica gel, amberlite IR-120 and sawdust were found to be 33.33, 25.19, and 33.67 mg g−1, respectively. Desorption study revealed that NaCl is one of the most appropriate desorbent. It may be concluded from this study that sawdust is a suitable sorbent due to low cost, abundant availability and recycling of the materials for further study.

Valorisation possibilities of exhausted biosorbents loaded with metal ions - A review

Biosorption is considered one of the most promising methods for removal of metal ions from aqueous effluents, due to its low-cost and eco-friendly characteristics. However, the exhausted biosorbents loaded with metal ions, obtained at the end of biosorption processes, are still a problem which should be solved to increase the applicability of biosorption on an industrial scale. In this study are examined three possibilities for the valorisation of exhausted biosorbents loaded with metal ions, namely: (i) regeneration and reuse of biosorbents in multiple biosorption cycles, (ii) the use of exhausted biosorbents as fertilizers for soils poor in essential microelements, and (iii) the pyrolysis of exhausted biosorbents, under well defined conditions. The main advantages and disadvantages of each valorisation possibility are reviewed in order to find the best way to use these cheap materials in accordance with the principles of the circular economy and thereby contributing to the development of sustainable biosorption technology.

Comparative uptake study of arsenic, boron, copper, manganese and zinc from water by different green microalgae

This work represents a comparative uptake study of the toxic elements arsenic, boron, copper, manganese and zinc in monometallic and multimetallic solutions by four green microalgae species (Chlamydomonas reinhardtii, Chlorella vulgaris, Scenedesmus almeriensis and an indigenous Chlorophyceae spp.), evaluating the effect of pH and contact time. Maximum removal efficiencies for each toxic element were 99.4% for Mn (C. vulgaris, pH 7.0, 3 h), 91.9% for Zn (Chlorophyceae spp., pH 5.5, 3 h), 88% for Cu (Chlorophyceae spp., pH 7.0, 10 min), 40.7% for As (S. almeriensis, pH 9.5, 3 h) and 38.6% for B (S. almeriensis, pH 5.5, 10 min). B removal efficiencies decreased remarkably in multimetallic solutions (down to 0.2% in C. reinhardtii), except for Chlorophyceae spp., the only species isolated from a polluted environment. FTIR spectra shown the highest interactions for As (1150-1300 cm^-1) and Cu (3300, 1741, 1535, 1350-1400 cm^-1). Results confirm microalgae biomass as a potential biosorbent for toxic elements.

Pb(II) Removal Process in a Packed Column System with Xanthation-Modified Deoiled Allspice Husk

The present research dealt with lead removal using modified Pimenta dioica L. Merrill as biosorbent in a batch and in continuous flow column systems, respectively. The allspice husk residues were modified first with a treatment through the xanthation reaction. For the adsorption tests, the atomic adsorption spectrophotometry method was used to determine the lead concentrations in the liquid samples. In the kinetic batch study (10 mg of sorbent in 10 mL of 25 mg L−1 lead solution), the removal efficiency was 99% (adsorption capacity of 25.8 mg g−1). The kinetic data followed the pseudo-second-order model. The adsorption isotherm was fitted to the Freundlich model, where constants were Kf and 1/n (8.06 mg(1-1/n) g−1 L1/n and 0.52), corresponding to adsorption capacities of 8 and 62 mg g−1, at liquid equilibrium concentration of 1 and 50 mg L−1, respectively. In the continuous flow systems where lead solution of 50 mg L−1 was treated in 2 columns of 5 cm (4.45 g) and 10 cm (9.07 g) bed heights, the dynamic adsorption capacity obtained by fitting the Thomas model was 29.114 mg g−1 and 45.322 mg g−1, respectively.

Removal of the metal ions from aqueous solutions by nanoscaled low molecular pectin isolated from seagrass Phyllospadix iwatensis

Pectins from sea grasses are considered as promising substances with pronounced metal-binding activity. Due to the high molecular weight and heterogeneous structure, the use of pectins for removal of metal ions is difficult. Technology of directed pectin degradation was developed and homogenous degraded nanoscaled pectin polymers were synthesized. Experimental samples of degraded pectin isolated from Phyllospadix iwatensis were tested for their metal binding activity in comparison with native pectin from this seagrass and commercial citrus pectin. The metal uptake of all pectin compounds was highest within the pH range from 4.0 to 6.0. The Langmuir, Freundlich and BET sorption models were applied to describe the isotherms and constants. Results showed that depolymerized pectin exerts highest lead and cadmium binding activity with pronounced affinity. All pectin compounds were suggested to be favorable sorbents. Therefore, it can be concluded that degraded pectin is a prospective material for creation of metal-removing water treatment systems.