Percorrer por autor "Kalmakhanova, Marzhan S."
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- Development and characterization of organically grafted clay minerals for the removal of methylene blue from waterPublication . Serikbayeva, Aizhan M.; Roman, Fernanda F.; Gomes, Helder T.; Kalmakhanova, Marzhan S.In recent years, water pollution caused by industrial waste has been a major problem throughout the world. To remove harmful impurities from water, using methylene blue (MB) as a model compound, modified clays were used, as they are capable of adsorbing various substances on their surfaces. The modified clays were obtained by grafting dimethyl sulfoxide (DMSO) and triethanolamine (TEOA) in the space between the layers of Shymkent clay. DMSO was first added to the natural clay; TEOA was also added at a temperature of 180°C and then held at that temperature for 2 h. The resulting modified clays were dried at 60°C for 24 h and characterized by X-ray diffraction (XRD), surface area analysis (SAA), Fourier-transform infrared spectroscopy (FT-IR), elemental analysis, and thermogravimetric analysis (DTA and TGA). Natural and modified clays (0.25–2.5 g L–1, pH=1–12, and 50°C) were used to adsorb MB from an aqueous solution at a concentration of 50 mg L–1. Contact with the adsorbent was maintained for 8 h. As much as 95.9% of the MB was removed from the aqueous solution in as little time as 15 min. Adsorption conditions were optimized, and the clay modified with TEAO showed better results than the natural clay (85% for modified clay vs 40% for original clay, at a clay concentration of 0.5 g L–1); significant adsorption was obtained over a wide pH range (>85% from pH 1 to 12).
- Environmental Impact of Wastewater on Surface and Groundwater in Central AsiaPublication . Kalmakhanova, Marzhan S.; Kurtebayeva, Assel A.; Tleuova, Zhanna T.; Satybaldiev, Bagdat; Orynbayev, Seitzhan A.; Malakar, Arindam; Gomes, Helder T.; Snow, Daniel D.This review aims to increase attention on present water quality issues on Central Asia, finding gaps in the literature on ways to address treatment needs, and help ensure future use of Central Asia surface waters and groundwater for all beneficial uses. Central Asia is a landlocked region known for its harsh climatic conditions and scarce water resources, despite being home to some of the world's largest internal drainage basins. The available literature suggests that increasing salinity has rendered water unsuitable for irrigation and consumption; hazardous trace elements are found throughout Central Asia, most often associated with mining and industrial sources; and that legacy pesticides influence water quality, particularly in agriculturally influenced basins. This study also focuses on the effects of municipal and industrial wastewater discharge. Additionally, the impact of inadequately treated wastewater on water resources is analyzed through a review of available data and reports regarding surface and groundwater quantity and quality. Given the challenges of water scarcity and accessibility, the reuse of treated wastewater is becoming increasingly important, offering a valuable alternative that necessitates careful oversight to ensure public health, environmental sustainability, and water security. However, due to insufficient financial and technical resources, along with underdeveloped regulatory frameworks, many urban areas lack adequate wastewater treatment facilities, significantly constraining their safe and sustainable reuse. Proper management of wastewater effluent is critical, as it directly influences the quality of both surface and groundwater, which serve as key sources for drinking water and irrigation. Due to their persistent and biologically active nature even at trace levels, we discuss contaminants of emerging concern such as antibiotics, pharmaceuticals, and modern agrochemicals. This review thus highlights gaps in the literature reporting on impacts of wastewater inputs to water quality in Central Asia. It is recommended that future research and efforts should focus on exploring sustainable solutions for water quality management and pollution control to assure environmental sustainability and public health.
- Interface-Controlled GO–CoFe2O4–Silicone Nanocomposite with Magnetic and Adsorptive FunctionalityPublication . Kudaibergenova, Rabiga M.; Anar, Aitekova R.; Demeuova, Gulzat K.; Murzakasymova, Nazgul S.; Kalmakhanova, Marzhan S.; Orynbayev, Seitzhan A.; Gomes, Helder T.; Sugurbekova, Gulnar K.The development of interface-engineered, multifunctional nanostructured materials with controllable surface and magnetic properties remains a critical challenge in wastewater treatment and environmental remediation. In this work, a novel GO-CoFe2O4-Silicone Magnetic Sponge was successfully fabricated through the integration of graphene oxide and CoFe2O4 magnetic nanoparticles within a silicone-modified porous sponge matrix. The resulting material combines superhydrophobicity, oleophilicity, high adsorption capacity, and magnetic responsiveness in a single architecture. The prepared sponge exhibited a high water contact angle of 161.5 degrees, confirming its superhydrophobic nature, while maintaining excellent structural integrity during repeated use. Vibrating sample magnetometry revealed clear ferrimagnetic behavior, enabling rapid magnetic manipulation and efficient recovery of the sponge from aqueous media. The GO-CoFe2O4-Silicone Magnetic Sponge demonstrated strong adsorption performance toward a wide range of oils and organic solvents, including chloroform, olive oil, toluene, ethanol, acetone, gasoline, and hexane, with adsorption capacities remaining stable over multiple cycles. Furthermore, the sponge showed outstanding separation efficiency exceeding 98.3% for various oil/water and organic solvent/water mixtures, both in batch and continuous vacuum-assisted separation systems. The adsorption capacity and separation efficiency were retained after repeated adsorption-desorption cycles, indicating excellent reusability and durability. Owing to its synergistic combination of surface chemistry, porous structure, and magnetic functionality, the GO-CoFe2O4-Silicone Magnetic Sponge represents a promising candidate for practical applications in oil spill cleanup and wastewater treatment.
- Permeable Reactive Barriers in Groundwater Remediation: A Review of Efficiency in Removing Pharmaceuticals and Heavy MetalsPublication . Kalmakhanova, Marzhan S.; Reimbayev, Yerbol K.; Karimbayeva, Zhanbike E.; Silva, Ana P. F.; Gomes, Helder T.Global water pollution driven by industrial and agricultural expansion has resulted in the widespread occurrence of persistent contaminants, particularly pharmaceuticals and heavy metals, in groundwater systems. Conventional treatment methods often prove inefficient, costly, and environmentally unsustainable, highlighting the need for innovative in situ remediation technologies. Permeable Reactive Barriers (PRBs) have emerged as a promising and energy-efficient solution for the long-term purification of contaminated aquifers. Their efficiency arises from passive operation, relying on natural groundwater flow to promote pollutant removal through adsorption, ion exchange, precipitation, and redox-driven transformations. This review emphasizes the superior performance of materials such as Activated Carbon, Biochar, Zeolites, and Zero-Valent Iron (ZVI) in the immobilization and reduction in pharmaceuticals and metal ions. Key challenges to PRB longevity include permeability loss and reactive media depletion due to mineral precipitation and biofouling. Advances in hybrid PRB configurations, coupled with electrokinetic (EK) and bioreactor systems, and predictive modeling, particularly Artificial Neural Networks (ANNs), offer pathways to enhance performance, optimize design, and ensure sustainable operation. Overall, PRBs represent a scalable and environmentally sound approach to groundwater remediation, with future progress relying on the development of multifunctional, regenerable materials and integrated design strategies.
- Sustainable Remediation of Pharmaceuticals Using Crop-Residue-Derived Carbons: Bridging Multi-Component Adsorption and DFT PerspectivesPublication . Kurtebayeva, Assel A.; Álvarez-Torrellas, Silvia; García, Juan; Gomes, Helder T.; Garrido-Zoido, Juan M.; Gil, Maria Victoria; Orynbayev, Seitzhan A.; Kalmakhanova, Marzhan S.This work is devoted to the synthesis and comprehensive study of activated carbons (ACs) obtained from agricultural wastes—specifically corn cob (C) and onion (O)—for the effective removal of paracetamol (PCM) and sulfamethoxazole (SMX) from aqueous media. The synthesis was carried out by chemical activation using H3PO4, HNO3, and NaOH as activating agents, which made it possible to obtain materials with a clearly defined microporous structure (microporous fraction Vmicro/Vtotal = 0.75–0.81) and specific surface chemistry. Particular attention was paid to studying the kinetics and equilibrium of adsorption in both single-component and binary (two-pollutant) systems. It was established that the equilibrium time is 8 h, and the experimental data are best described by a pseudo-second-order kinetic model. During binary adsorption tests, the competitive behavior was observed for certain materials, such as the corn-derived carbon activated with HNO3 (AC-CN) and the onion-derived carbon activated with HNO3 (AC-ON), where molecules compete for active sites. Conversely, synergistic effects were identified in other systems, controlled by specific surface-functional groups and hydration effects. The maximum adsorption capacity was found to be 29.4 mg∙g−1 for PCM on the AC-CN sample. Adsorption mechanisms, including multilayer isotherm profiles and the competition between pollutant and water molecules, were interpreted using quantum chemical calculations within the framework of Density Functional Theory (DFT). These calculations revealed that partial deprotonation and intense solvation of SMX molecules at natural pH reduce their adsorption capacity. In contrast, the PCM structure favors π-π interactions and the formation of strong hydrogen bonds with oxygen-containing groups on the carbon surface. These results demonstrate the high potential of using agro-industrial waste to create a new generation of selective adsorbents with tailored surface properties.
- Use of Permeable Reactive Barriers in the Removal of ACT and DCF from Effluents of Wastewater Treatment PlantsPublication . Kalmakhanova, Marzhan S.; Khabashova, Aidana U.; Nurlybayeva, Aisha N.; Orynbayev, Seitzhan A.; Gomes, Helder T.; Snow, Daniel D.Pharmaceuticals such as paracetamol and diclofenac (DCF) are among the most extensively consumed drugs worldwide and are continuously released into municipal and hospital wastewater due to incomplete human metabolism. Their persistent presence in aquatic environments, typically ranging from ng/L to µg/L, raises concerns due to endocrine disruption, chronic toxicity, and the promotion of antimicrobial resistance. Conventional wastewater treatment plants (WWTPs) remove 70–90% of ACT but less than 30% of DCF, primarily because these systems were not designed to target low-concentration, recalcitrant micropollutants. As a result, pharmaceuticals frequently pass into treated effluents, highlighting the need for advanced, sustainable, and passive treatment solutions. Permeable reactive barriers (PRBs) have emerged as a promising technology for the interception and removal of pharmaceuticals from both wastewater treatment plant effluents and groundwater. This review provides a comprehensive assessment of ACT and DCF occurrence, environmental behavior, and ecotoxicological risks, followed by a detailed evaluation of PRB performance using advanced reactive media such as geopolymers, activated carbon, carbon nanotubes, and hybrid composites. Reported removal efficiencies exceed 90% for ACT and 70–95% for DCF, depending on media composition and operating conditions. The primary removal mechanisms include adsorption, ion exchange, π–π interactions, hydrogen bonding, and redox transformation. The novelty of this review lies in systematically synthesizing recent laboratory and pilot-scale findings on PRBs for pharmaceutical removal, identifying critical knowledge gaps including long-term field validation, media regeneration, and performance under realistic wastewater matrices and outlining future research directions for scaling PRBs toward full-scale implementation. The study demonstrates that PRBs represent a viable and sustainable tertiary treatment option for reducing pharmaceutical loads in aquatic environments.