This study explores the utilization of waste grape pomace-derived hydrochar as an efficient adsorbent for lead (Pb²⁺) removal from aqueous solutions. Hydrochar was produced via hydrothermal carbonization (HTC) at 220 °C, followed by doping with magnesium and iron salts, and subsequent pyrolysis at 300 °C to obtain Fe/Mg-pyro-hydrochar (FeMg-PHC). The material’s structural and morphological changes after Pb²⁺ adsorption were examined using FTIR. FTIR revealed chemisorption and ion exchange as key mechanisms, shown by decreased hydroxyl, carbonyl, and metal–oxygen peaks after Pb²⁺ adsorption. Adsorption tests under varying pH, contact time, and initial Pb²⁺ concentrations revealed optimal removal at pH 5. Kinetic modeling indicated that the process follows a pseudo-second-order model, suggesting chemisorption as the dominant mechanism. Isotherm analysis showed that the Sips model best describes the equilibrium, with a maximum theoretical adsorption capacity of 157.24 mg/g. Overall, the simple two-step synthesis—HTC followed by pyrolysis—combined with metal doping yields a highly effective and sustainable adsorbent for Pb²⁺ ion removal from wastewater.

Plastic handling and manufacturing have recently increased dramatically owing to technological advancements and rising living standards. Consequently, the amount of plastic waste has significantly escalated, seriously pressuring the whole ecosystem. The impacts of waste accumulation in the environment frequently have detrimental effects on living organisms. Sustainable development goals (SDGs) propose balanced and feasible development of entire humanity, protecting natural resources and bringing a clean environment. Poly (ethylene terephthalate) - PET is a common plastic that can seriously threaten the environment if it is not handled appropriately. This review paper tends to show recent trends in the production and recycling of PET polymer on a global scale. The basis of PET chemistry together with possible applications was presented. A target period, from 2020-2024, was used to examine the quantity and main industrial suppliers around the world. Therefore, some sources state that in 2024, nearly 28 Mt of PET was produced and China was the main producer with a global share of 31%. Adequate management of the mentioned polymer is necessary for building an eco-friendly climate for future generations.

This article provides a comprehensive review of recent advancements in biopolymer technology, focusing on their environmental and economic impact across various industries. Key biopolymers discussed include cellulose, lignin, starch, algal polysaccharides, and protein-based polymers such as whey and casein, alongside essential biopolymers like chitin, chitosan, pectin, guar gum, xanthan gum, natural polyesters, and polyamides. These biopolymers have experienced rising demand due to their renewable nature and biodegradability, supporting the shift toward sustainable materials in sectors such as food technology, biomedical applications, and eco-friendly packaging. By synthesizing insights from industry reports, market trends, and scientific studies, the review highlights the growth trajectory, environmental benefits, and economic viability of biopolymers. The analysis emphasizes how these materials contribute to reducing fossil fuel dependency and waste, positioning them as critical components of the green economy. Furthermore, it addresses challenges such as production costs and scalability, advocating for ongoing research and technological development to maximize their potential. This work underscores the increasingly vital role of biopolymers in sustainable development and sets the stage for further innovation in the field.

The reserves of rich ores, from which the production of zinc by the existing conventional roasting-leaching-electrowinning process is technologically possible and economically justified, are decreasing year by year. For this reason, increasing attention has been directed towards researching the possibility of obtaining zinc from complex polymetallic ores with a low metal content, adhering to sustainable development goals following strict environmental regulations. Leaching procedures are commonly utilized for the processing of such mineral raw materials.As sphalerite is the widespread and most significant mineral of zinc sulfide, a large part of the research focuses on studying the behavior of sphalerite in the leaching process. This paper reviews the existing knowledge about the leaching of sphalerite in acidic solutions as well as the phenomena accompanying the dissolution process. Special attention is given to research related to the kinetics and mechanism of sphalerite oxidation in an acidic medium influenced by various oxidants, such as hydrogen peroxide, oxygen, dichromate ions, nitrate and nitrite ions, ferric and cupric ions, and others. All these results enable the development of new technological procedures to produce zinc from low-grade and complex ores while meeting increasingly rigorous environmental requirements.

Electric waste from numerous devices that are put out of use every day has some form of printed circuit board that contains precious and valuable metals in their components. In order to extract these metals, the printed circuit boards were crushed and pyrolyzed into powder. The fine pyrolyzed printed circuit board (PPCB) powder was separated into fractions, and the fine metallic fraction was used as a raw material for metal leaching extraction. In order to better understand how various metal species react in leaching media, several leaching agents were used (sulfuric acid, nitric acid, glycine, and acid mine drainage-AMD) alone, and with the addition of hydrogen peroxide. Additionally, the influence of the S/L ratio and leaching temperature were investigated in sulfuric acid leaching solutions, as this is the one most widely used. In one case, the reactor was heated in a thermal bath, while in the other, it was heated in an ultrasonic bath. Lastly, several experiments were conducted with a (consecutive) two-pronged leaching approach, with and without applied pretreatment. The aim of this paper is to give a multifocal and detailed approach to how metals such as Al, Cu, Co, Zn, Sn, and Ca behave when extracted from fine PPCB powder. However, some attention is given to Nd, Pd, Pb, and Ba as well. One of the main findings is that regardless of the pretreatment or the sequence of leaching media applied, consecutive two-pronged leaching cannot be used for selective metal extraction. However, AMD was found to be suitable for selective leaching with very limited applications.