A Critical Overview of Adsorption Models Linearization: Methodological and Statistical Inconsistencies

Adsorption dynamics of Cd2+(aq) on microwave-synthetized pristine biochar from cocoa pod husk: Green, experimental, and DFT approaches

Biochar obtained via microwave-assisted pyrolysis (MAP) at 720 W and 15 min from cocoa pod husk (CPH) is an efficient adsorbent of Cd2+(aq). Biochar of residual biomass of CPH (BCCPH) possesses favorable physicochemical and morphological properties, featuring a modest surface area yet a suitable porous structure. Adsorption, predominantly governed by physisorption, is influenced by the oxygen-containing active sites (-COOR, -C(R)O, and -CH2OR; R = H, alkyl). CdCO3 formation occurs during adsorption. Experimental data were well-fitted into various kinetic models for a broad understanding of the sorption process. Langmuir model indicates a maximum adsorption capacity of 14.694 mg/g. The thermodynamic study confirms the spontaneous and endothermic sorption. Studies at the molecular level have revealed that the Cd2+ ion tends to bind to surface aromatic carbon atoms. This sustainable approach produces BCCPH via MAP as a solution for waste transformation into water-cleaning materials.

Advancements in application of modified biochar as a green and low-cost adsorbent for wastewater remediation from organic dyes

Synthetic organic dyes, which are resistant to biodegradation, pose a notable health risk, potentially leading to cancer and respiratory infections. Researchers have addressed this concern by exploring physicochemical methods to remove organic dyes from wastewater. A particularly promising solution involves modified biochar adsorbents, which demonstrate high efficiency in organic dye removal. Biochar, a charcoal-like material derived from biomass pyrolysis, offers advantages such as low cost, eco-friendliness, high efficiency and reusability. Beyond its role in sustainable soil remediation, biochar proves effective in removing organic dyes from wastewater after undergoing physical or chemical modification. Acid-base activation or metal-heteroatom impregnation enhances biochar's adsorption capacity. This comprehensive review examines the attributes of biochar, common methods for production and modification, and the impacts of raw materials, pyrolysis temperature, heating rate and residence time. It further elucidates the biochar adsorption mechanism in the removal of organic dyes, assessing factors influencing efficiency, including biochar feedstock, solution pH, adsorption temperature, particle size, initial dye concentration, biochar dosage and reaction time. It explores challenges, opportunities, reusability and regeneration methods of biochar in treating organic dye wastewater. It also discusses recent advances in organic dye removal using adsorption-based biochar. The review ultimately advocates for enhancing biochar's adsorption performance through post-modification.

Discussion on the thermodynamic calculation and adsorption spontaneity re Ofudje et al. (2023)

Accurate calculations and precise results are very important for the dissemination of scientific knowledge, whereas the errors of calculation will diminish the academic value of the paper. This discussion focuses on the calculation of thermodynamics and the determination of the spontaneity of adsorption processes in the paper of Ofudje et al. (2023). Ofudje et al. found that the apatite synthesized by chemical method (CHAp) has excellent adsorption properties for cadmium ions, which is an important contribution to the remediation of cadmium pollution. However, the calculation results of standard Gibbs free energy change (ΔGo), standard enthalpy change (ΔHo) and standard entropy change (ΔSo) of the adsorption of Cd2+ onto CHAp surface need to be corrected due to an incorrect calculation. Firstly, the partition coefficient (KD) with a dimension cannot be used for thermodynamic calculation. Secondly, the adsorbent mass (m) described by Ofudje et al. in different Sections is inconsistent, leading to incorrect results of Ko and ΔGo. When the appropriate value of the adsorbent mass is selected and the partition coefficient is converted to the standard adsorption equilibrium constant Ko, the calculated ΔGo is less than zero, which means that the adsorption is spontaneous. This discussion provides the correct calculation method of standard adsorption equilibrium constants and thermodynamic parameters, which can improve the reader's judgment and understanding of adsorption spontaneity.

Integrated photocatalysis adsorption processes for oxytetracycline removal: using volborthite and its composite with g-C3N4

The photocatalytic-adsorption performance of the composites of volborthite (CuVA) and graphitic carbon nitride (g-C3N4) was studied in this work using oxytetracycline (OTC) as model pollutant under LED light irradiation. CuVA at different weight percentages (10, 30, 50), namely, C10, C30, and C50, were loaded onto graphitic carbon nitride using wet chemical method. The physical, chemical, and optical properties were evaluated via various analytical techniques. Through integrated adsorption-photocatalytic process, no significant photocatalytic reaction occurred in g-C3N4 and the composite even after 4 h of irradiation. The setup was modified such that each run was conducted in the presence and absence of light. Aside from photolysis and g-C3N4, all composites performed better under the presence of light in which CuVA improved the most from ~ 50% down to ~ 20% of initial concentration. CuVA performed almost identically (80% removal of OTC) under the presence of light irradiation at ambient temperature (22 °C) and in the dark at 32 °C, confirming that temperature was the contributing factor to the improvement instead of light. CuVA exhibited excellent adsorption capacity of 171 mg/g and adsorption rate of 90% towards the removal of highly concentrated OTC (100 mg/L) under optimized parameters of pH 5.0 and at 42 °C after 3 h of adsorption process. Life cycle assessment revealed that close to 50% of fresh 100 ppm OTC could be removed after five cycles without any desorption process.

A two-in-one thiosemicarbazide and whole pine needle-based adsorbent for rapid and efficient adsorption of methylene blue dye and mercuric ions

Herein, we report the synthesis of an oxidized pine needle-thiosemicarbazone Schiff base (OPN-TSC) from whole pine needles (WPN) as a dual-purpose adsorbent to remove a cationic dye, methylene blue (MB), and Hg2+ ions in separate processes. The adsorbent was synthesized by periodate oxidation of WPN followed by a reaction with thiosemicarbazide. The syntheses of OPN and OPN-TSC were confirmed by FTIR, XRD, FESEM, EDS, BET, and surface charge analysis. The emergence of new peaks at 1729 cm-1 (-CHO stretching) and 1639 cm-1 (-COO- stretching) in the FTIR spectrum of OPN confirmed the oxidation of WPN to OPN. FTIR spectrum of OPN-TSC has a peak at 1604 cm-1 (C = N stretching), confirming the functionalization of OPN to OPN-TSC. XRD studies revealed an increase in the crystallinity of OPN and a decrease in the crystallinity of OPN-TSC because of the attachment of thiosemicarbazide to OPN. The values of %removal for MB and Hg2+ ions by OPN-TSC were found to be 87.36% and 98.2% with maximum adsorption capacity of 279.3 mg/g and 196 mg/g for MB and Hg2+ ions, respectively. The adsorption of MB followed pseudo-second-order kinetics with correlation coefficient (R2 of 0.99383) and Freundlich isotherm (R2 = 0.97239), whereas Hg2+ ion removal demonstrated the Elovich (R2 = 0.97076) and Langmuir isotherm (R2 = 0.95110). OPN-TSC is regenerable with significant recyclability up to 10 cycles for both the adsorbates. The studies established OPN-TSC as a low-cost, sustainable, biodegradable, environmentally benign, and promising adsorbent for the removal of hazardous cationic dyes and toxic metal ions from wastewater and industrial effluents, especially the textile effluents.

Comment on "Magnetic tubular nickel@silica-graphene nanocomposites with high preconcentration capacity for organothiophosphate pesticide removal in environmental water: Fabrication, magnetic solid-phase extraction, and trace detection" [J. Hazard. Mater. 457 (2023) 131788]

The field of adsorption is seen with mistrustfulness by Scientific Society. One of these reasons is that many users of adsorption do not have knowledge of several concepts of physical chemistry, and they spread misconceptions throughout the literature. One point that is usually found to be wrong in papers published even in prestigious Journals involving adsorption is the thermodynamics of adsorption, the use of linearization for modeling the equilibrium and kinetics of adsorption, and other misconceptions related to adsorption. In the paper, Journal of Hazardous Materials 457 (2023) 131788, some inconsistencies related to adsorption are seen, and this letter intends only to correct these small mistakes and not overrule the scientific content of this publication.

Sulfate radical-based advanced oxidation process effects on tire wear particles aging and ecotoxicity

Tire wear particles (TWPs) are widely distributed in natural water and pose as major pollutants in aquatic environments. In this study, heat-activated persulfate (HPT) and ultraviolet-activated persulfate treatments (UPT) were employed to investigate the influence of sulfate radical (SO4-•)-based advanced oxidation process (SAOPs) on TWP physicochemical properties and to clarify their ecotoxic effects in laboratory-level studies. Results showed that the specific surface areas of TWPs increased after UPT but decreased after HPT. In terms of chemical properties, the increase of oxygen-containing functional groups on the surfaces of TWPs was more evident in UPT than that in HPT. The atrazine (ATZ) adsorption capacity of TWPs after HPT and UPT was increased compared with the untreated TWPs. Atrazine adsorbed by TWPs was easily resolved and released in artificial intestinal fluid (1.89-2.08 mg/g) and artificial gastric fluid (1.60-2.04 mg/g) conditions. Acute toxicity experiments of Photobacterium phosphoreum and SEM-EDS detection results suggested that various heavy metals (e.g., Zn2+, Cu2+) in the TWPs would be released into the water system in SAOPs. ATZ released from TWPs that adsorbed ATZ herbicide, rather than TWPs themselves, had a negative effect on aquatic plant growth (e.g., C. vulgaris). The leaching solution of oxidized TWPs (after HPT and UPT) showed a more significant inhibition effect on the zebrafish survival compared with that of untreated TWPs, which was possibly caused by the generation of oxidation byproducts such as N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine-quinone.

Uncovering the intricate relationship between plant nutrients and microplastics in agroecosystems

Recent scientific and media focus has increased on the impact of microplastics (MPs) on terrestrial and soil ecosystems. However, the interactions between MPs with macronutrients and micronutrients and their potential consequences for the agroecosystem are not well understood. Wheat (Triticum aestivum) is a staple food grown globally and has special importance for nations economies. Different elements can cause dangerous outcomes for wheat quality and production yield. In this study, batch adsorption experiments were done using 1 g of polyethylene tetra phthalate MP particles (PET-MPs) in varying concentrations of thirteen elements. The adsorption data were fitted by two common adsorption models (Langmuir and Freundlich). The effect of pH on the speciation of elements in aqueous solutions was investigated. The non-invasive characterization methods indicate the importance of O- and H-containing groups as the main component of selected MPs in controlling the adsorption of the elements ions. In the current study, adsorption and potential transport of the adsorbed macronutrients (K and Na) and micronutrients (Ni, Co, Cu, Al, Ba, Se, Fe, As, B, V and Ag) which include some beneficial (Na, Se, V), and non-essential or toxic elements (Al, As, Ag, Ba) onto MPs to the simulated roots of wheat were evaluated. The maximum sorption capacities of K+> Ni+2> Na+ > Co2+> Cu2+>Al+3 >Ba+2 >Se4+>Fe2+ >As5+ >B3+ >V5+> Ag + on PET-MPs at pH 5.8 and 25 ± 1 °C were 290.6 > 0.52> 0.51 > 0.20> 0.10 > 0.051> 0.024 > 0.003> 0.003 > 0.0015> 5.05 × 10-4> 1.7 × 10-4>3.7 × 10-6 mg g-1, respectively. The results highlight the importance of PET-MPs in controlling element adsorption in the rhizosphere. Our observations provide a good start for understanding the adsorption of multiple elements from the soil rhizosphere zone by PET-MPs.

Fixed-bed column adsorption modeling using Zr biocomposites for fluoride removal

This research involved conducting continuous adsorption experiments to assess fluoride elimination from drinking water achieved by utilizing biocomposites created from the peels of oranges and apples, which were impregnated with zirconium (Zr), to form BOP-Zr and BAP-Zr, respectively. The findings from the experimental data indicate that BOP-Zr and BAP-Zr are effective biosorbents with a solid ability to remove fluoride selectively. Additionally, these biosorbents were found to be stable, as they do not release Zr into the treated water. Notably, these environmentally friendly biosorbents are derived from renewable sources and enhance the value of waste materials. The study employed various empirical models, including Bohart-Adamas, Thomas, Yoon-Nelson, BDST, Clark, Yan, and Woolborska, to elucidate the mechanisms and crucial parameters involved in fluoride adsorption within packed bed columns. The Yan model demonstrated the highest correlation among these models, indicating a chemical adsorption process with kinetics following a pseudo-second-order pattern. BOP-Zr and BAP-Zr exhibited a maximum adsorption capacity of 59.3 and 47.5 mg/g, respectively, under a flow rate of 4 mL/min and an inlet fluoride concentration of 25 mg/L. The analysis of mass transfer coefficients revealed that the primary step governing the adsorption procedure was diffusion through pores. Consequently, the study conclusively establishes that BOP-Zr and BAP-Zr biocomposites, originating from lignocellulosic biomass remains, present a practical and competitive choice for eliminating fluoride from water. These materials surpass waste materials in performance and rival more expensive options in efficiency and performance.

Controversial Issues Related to Dye Adsorption on Clay Minerals: A Critical Review

This critical review points out the most serious and problematic issues to be found in the literature on the adsorption of dyes on clay minerals. The introduction draws attention to the fundamental problems, namely the insufficient characterization of adsorbents, the influence of impurities on the adsorption of dyes, and the choice of inappropriate models for the description of the very complex systems that clay minerals and their systems represent. This paper discusses the main processes accompanying adsorption in colloidal systems of clay minerals. The relationship between the stability of the colloidal systems and the adsorption of dye molecules is analyzed. The usual methodological procedures for determining and evaluating the adsorption of dyes are critically reviewed. A brief overview and examples of modified clay minerals and complex systems for the adsorption of organic dyes are summarized. This review is a guide for avoiding some faults in characterizing the adsorption of organic dyes on clay minerals, to improve the procedure for determining adsorption, to evaluate results correctly, and to find an appropriate theoretical interpretation. The main message of this article is a critical analysis of the current state of the research in this field, but at the same time, it is a guide on how to avoid the most common problems and mistakes.

KMnO4-oxidized whole pine needle based adsorbent for selective and efficient removal of cationic dyes

In the present study, we report the chemical modification of the dried and fallen pine needles (PNs) via a simple protocol using KMnO4 oxidation. The oxidized PNs (OPNs) were evaluated as adsorbents using some cationic and anionic dyes. The successful synthesis of OPNs adsorbent was characterized by various techniques to ascertain its structural attributes. The adsorbent showed selectivity for the cationic dyes with 96.11% removal (Pr) for malachite green (MG) and 89.68% Pr for methylene blue (MB) in 120 min. Kinetic models namely, pseudo-first order, pseudo-second order, and Elovich were applied to have insight into adsorption. Additionally, three adsorption isotherms, i.e., Langmuir, Freundlich, and Temkin were also applied. The dye adsorption followed a pseudo-second-order kinetic model with R2 > 0.99912 for MG and R2 > 0.9998 for MB. The adsorbent followed the Langmuir model with a maximum adsorption capacity (qm) of 223.2 mg/g and 156.9 mg/g for MG and MB, respectively. Furthermore, the OPNs showed remarkable regeneration and recyclability up to nine adsorption-desorption cycles with appreciable adsorption for both the dyes. The use of OPNs as an adsorbent for the removal of dyes from wastewater, therefore, provides an ecologically benign, low-cost, and sustainable solution.

A critical review of adsorption isotherm models for aqueous contaminants: Curve characteristics, site energy distribution and common controversies

The quantitative description of the equilibrium data by the isotherm models is an indispensable link in adsorption studies. The previous review papers focus on the underlying assumptions, fitting methods, error functions and practical applications of the isotherm models, usually ignoring their curve characteristics, selection criteria and common controversies. The main contents of this review include: (i) effect of the model parameters on the isotherm curves; (ii) determination of the site energy distribution; (iii) selection criteria of the isotherm models; and (iv) elimination of some common controversies. It is of great significance to reveal the curve characteristics for selecting a proper isotherm model. The site energy distribution is conducive to understanding the physicochemical properties of the adsorbent surface. The complete isotherm is recommended to be correlated with the experimental data. The model parameter q_max should be cautiously adopted for comparison of the adsorbent performance. The residual plot can be used to diagnose the fitting quality of the isotherm models further. This review also addresses some common mistakes and controversies and thereby avoids their propagation in future publications.

Sorption of representative organic contaminants on microplastics: Effects of chemical physicochemical properties, particle size, and biofilm presence

Microplastic pollution has attracted mounting concerns worldwide. Microplastics may concentrate organic and metallic contaminants; thus, affecting their transport, fate and organismal exposure. To better understand organic contaminant-microplastic interactions, our study explored the sorption of selected polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), α-hexabromocyclododecane (α-HBCDD), and organophosphate flame retardants (OPFRs) on high-density polyethylene (HDPE) and polyvinylchloride (PVC) microplastics under saline conditions. Sorption isotherms determined varied between chemicals and between HDPE and PVC microplastics. Log Freundlich sorption coefficients (Log K_F) for the targeted chemicals ranged from 2.01 to 5.27 L kg^-1 for HDPE, but were significantly lower for PVC, i.e., ranging from Log K_F data (2.84 - 8.58 L kg^-1). Significant correlations between chemicals' Log K_F and Log K_ow (octanol-water partition coefficient) indicate that chemical-dependent sorption was largely influenced by their hydrophobicity. Sorption was evaluated using three size classes (< 53, 53 - 300, and 300 - 1000 µm) of lab-fragmented microplastics. Particle size did not significantly affect sorption isotherms, but influenced the time to reach equilibrium and the predicted maximum sorption, likely related to microplastic surface areas. The presence of biofilms on HDPE particles significantly enhanced contaminant sorption capacity, indicating more complex sorption dynamics in the chemical-biofilm-microplastic system. Our findings offer new insights into the chemical-microplastic interactions in marine environment.

Adsorption of naphthalene and its derivatives onto high-density polyethylene microplastic: Computational, isotherm, thermodynamic, and kinetic study

Microplastics (MP) have received great attention due to the mass-produced residues discharged into the environment. MP are ideal for adhering to organic pollutants that can be easily dispersed, thus posing risks to human health. Furthermore, little has been reported on how different functional groups in polycyclic aromatic hydrocarbons (PAH) derivatives influence the adsorption behavior on MP. To better understand this process, groups methyl (-CH₃) and hydroxyl (-OH) were selected and commercial and waste high-density polyethylene (HDPE, ≤ 1 mm) were used as adsorbents, and Naphthalene (Nap), 1-Methyl-Naphthalene (Me-Nap) and α-Naphthol as adsorbates. The results showed different behaviors for nonpolar and polar adsorbates. Dispersion forces were the main type of interaction between HDPE and Nap/Me-Nap, while dipole-induced dipole forces and H-bonding were the chief interactions involving MP and polar compounds. Regardless the HDPE source, Nap and Me-Nap have a Type III isotherm, and α-Naphthol presents a Type II isotherm. Nap and Me-Nap fitted to Freundlich isotherm of an unfavorable process (n = 2.12 and 1.11; 1.87 and 1.31, respectively), with positive values of ΔH° (50 and 77.17; 66 and 64.63 kJ mol^-1) and ΔS° (0.070 and 0.0145; 0.122 and 0.103 kJ mol^-1) for commercial and waste MP, respectively. Besides, the adsorption isotherm of α-Naphthol on commercial and waste HDPE fitted to the Langmuir model (Q_max = 42.5 and 27.2 μmol g^-1, respectively), presenting negative values of ΔH° (-43.71 and -44.10 kJ mol^-1) and ΔS° (-0.037 and -0.025 kJ mol^-1). The adsorption kinetic study presents a nonlinear pseudo-second-order model for all cases. The K₂ values follow the order Me-Nap > Nap > α-Naphthol in both MP. Therefore, this experimental study provides new insights into the affinity of PAH derivatives for a specific class of MP, helping to understand the environmental fate of residual MP and organic pollutants.

Adsorption of SARS-CoV-2 onto granular activated carbon (GAC) in wastewater: Implications for improvements in passive sampling

Based on recent studies, passive sampling is a promising method for detecting SARS-CoV-2 in wastewater surveillance (WWS) applications. Passive sampling has many advantages over conventional sampling approaches. However, the potential benefits of passive sampling are also coupled with apparent limitations. We established a passive sampling technique for detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in wastewater using electronegative filters. Though, it was evident that the adsorption capacity of the filters constrained their use. This work intends to demonstrate an optimized passive sampling technique for SARS-CoV-2 in wastewater using granular activated carbon (GAC). Through bench-scale batch-adsorption studies and sewershed deployments, we established the adsorption characteristics of SARS-CoV-2 and two human feacal viruses (PMMoV and CrAssphage) onto GAC. A pseudo-second-order model best-described adsorption kinetics for SARS-CoV-2 in either deionized (DI) water and SARS-CoV-2, CrAssphage, and PMMoV in wastewater. In both laboratory batch-adsorption experiments and in-situ sewershed deployments, the maximum amount of SARS-CoV-2 adsorbed by GAC occurred at ~60 h in wastewater. In wastewater, the maximum adsorption of PMMoV and CrAssphage by GAC occurred at ~60 h. In contrast, the adsorption capacity was reached in DI water seeded with SARS-CoV-2 after ~35 h. The equilibrium assay modeled the maximum adsorption quantity (q_max) in wastewater with spiked SARS-CoV-2 concentrations using a Hybrid Langmuir-Freundlich equation, a q_max of 2.5 × 10⁹ GU/g was calculated. In paired sewershed deployments, it was found that GAC adsorbs SARS-CoV-2 in wastewater more effectively than electronegative filters. Based on the anticipated viral loading in wastewater, bi-weekly sampling intervals with deployments up to ~96 h are highly feasible without reaching adsorption capacity with GAC. GAC offers improved sensitivity and reproducibility to capture SARS-CoV-2 RNA in wastewater, promoting a scalable and convenient alternative for capturing viral pathogens in wastewater.

Operational Constraints of Detecting SARS-CoV-2 on Passive Samplers using Electronegative Filters: A Kinetic and Equilibrium Analysis

In developing an effective monitoring program for the wastewater surveillance of SARS-CoV-2 ribonucleic acid (RNA), the importance of sampling methodology is paramount. Passive sampling has been shown to be an effective tool to detect SARS-CoV-2 RNA in wastewater. However, the adsorption characteristics of SARS-CoV-2 RNA on passive sampling material are not well-understood, which further obscures the relationship between wastewater surveillance and community infection. In this work, adsorption kinetics and equilibrium characteristics were evaluated using batch-adsorption experiments for heat-inactivated SARS-CoV-2 (HI-SCV-2) adsorption to electronegative filters. Equilibrium isotherms were assessed or a range of total suspended solids (TSS) concentrations (118, 265, and 497 mg L-1) in wastewater, and a modeled qmax of 7 × 103 GU cm-2 was found. Surrogate adsorption kinetics followed a pseudo-first-order model in wastewater with maximum concentrations achieved within 24 h. In both field and isotherm experiments, equilibrium behavior and viral recovery were found to be associated with wastewater and eluate TSS. On the basis of the results of this study, we recommend a standard deployment duration of 24-48 h and the inclusion of eluate TSS measurement to assess the likelihood of solids inhibition during analysis.

Biosorption of nickel ions Ni2+ by natural and modified Pinus caribaea Morelet sawdust

The potential of Pinus caribaea Morelet sawdust for the removal of nickel ions (Ni²⁺) and other metallic trace ions (Co²⁺, Cr³⁺, Mn²⁺) from aqueous solutions was investigated under batch conditions. Several parameters such as size of particles, contact time, pH, initial metal and biomass concentrations, desorption conditions and reusability were evaluated on natural biomass. Biosorption was fast, effective (73%) and biomaterial can be reused after five cycles. To enhance the removal capacity of nickel, pine sawdust was modified by acidic and oxidative treatments. Cellulosic residues from sawdust sequential extraction showed great biosorption capacity (96%). In the presence of a metal mixture, oxidized sawdust had better selectivity for Cr³⁺ ions than for Ni²⁺. Pinus caribaea biomass could be an environmental, inexpensive and renewable material for the depollution of water laden with metallic trace elements.

•

Pinus caribaea sawdust is an effective biosorbent of metallic trace elements.

•

High Ni²⁺ removal efficiency was observed at pH 8 with 5 g/L of biosorbent.

•

Equilibrium adsorption was described by Freundlich and Langmuir isotherms.

•

Pine sawdust is a reusable biosorbent with good desorption capacity.

•

Efficiency of acidified and oxidized adsorbents.

Effectiveness and Characterization of Novel Mineral Clay in Cd2+ Adsorption Process: Linear and Non-Linear Isotherm Regression Analysis

The excellent adsorption properties of clay minerals make the optimization of heavy metal removal the subject of numerous research projects. In the present study, ASLAVITAL cosmetic clay (ACC) powder was applied for the removal of Cd2+ from water. The main deposit of ACC clay is the Pădurea Craiului Mountains in Romania. A wide range of morpho-structural approaches (SEM, EDX, FTIR, Raman, XRD) were used to characterize the morphology and elemental composition of the adsorbent. As expected for clay minerals, Al (Wt(%) = 11.4 ± 0.9) and Si (Wt(%) = 13.7 ± 1.4) are the main constituents of ACC. After adsorption, Wt(%) = 0.2 ± 0.01 Cd2+ was detected in the sample. As proved before, the initial metal concentration is the primary influencing factor; therefore, batch adsorption of 10–160 mg/L Cd2+ was investigated. After 190 min, an efficiency of 99% was reached, and the quantity in equilibrium increased from 1–8 mg/g. The best fit in linear form was obtained for the Langmuir II. model, where R2 = 0.954 (RL = 0.037–0.027). Based on linear isotherm models, physical bonds formed between ACC and Cd2+ during the favorable adsorption. For the non-linear fits, the Liu model proved to be the best R2 = 0.965, χ2 = 1.101. Pseudo-II-order kinetic model described the experimental data R2 = 0.988–0.999; qexp and qcalc were almost identical (the differences ranged 0.03–0.34).