Journal of Water Chemistry and Technology最新文献

Aquatic life is largely affected by the toxic nature of pharmaceutical waste that is released into the environment and affects nature at every level. To preserve nature, it is very important to remove pharmaceutical waste, such as ciprofloxacin (CIP) and other antibiotics from nature. In this study, chitosan-graphene-based eco-friendly nano-adsorbent (CS-GO-NPs) was synthesized for the removal of CIP from an aqueous medium using ultrasonic-assisted adsorption. A detailed analysis of process conditions including pH, initial concentration, adsorbent dose, and temperature was performed. Results were found to be significant and more than 94% removal efficiency was achieved using an optimum concentration of 200 mg/L, 5 pH, and adsorption time of 20 min. Further, batch adsorption data was used to study the kinetic and thermodynamic behavior and an isotherm study was performed to determine the adsorbate-adsorbent interaction. Experimental results showed a significant agreement with the theoretical values and more than 0.99 regression coefficient (R²) values were obtained for pseudo-second-order and Freundlich isotherm. Further, an adsorption mechanism was also proposed for the CIP-(CS-GO-NPs) system, and found that film diffusion dominates the process, while pore diffusion also plays a vital role in devising an effective eco-friendly adsorbent. The proposed study provides an effective and sustainable route for the management of toxic pharmaceutical wastes using chitosan-graphene-based nano-adsorbent under mild process conditions.

The China-Pakistan Economic Corridor (CPEC) between China and Pakistan passes through the environmentally fragile region of the Himalayas−Karakorum−Hindukush (HKH). Surging human influence in the form of transportation and tourism may pose a potential threat to the socio-environmental sustainability especially, the water resources of the region. Therefore, it is important to evaluate the status and hydrogeochemistry of freshwater in mountainous catchments. For this purpose, water samples were collected from the Hunza, Gilgit, and Indus River Basins from 2019 to 2020. The physicochemical and biological characteristics of surface water were investigated using the water quality index (WQI), multivariate statistics, Piper diagram, and Gibbs plots. The results revealed high seasonal variability in the hydrochemistry of water samples in all basins. Heavy metals (HM) i.e., arsenic (As), and lead (Pb) were detected in more than 50% of total water samples, whereas cadmium (Cd) and mercury (Hg) were detected in less than 15% of total water samples. 82% of water samples collected during summer and 48% in winter were contaminated with bacterial contamination (Escherichia coli (E. coli) and total coliform (T. coli)). Piper diagram and Gibbs plot suggested that rock weathering and dissolution of carbonate rocks are the dominating factors controlling the chemistry of glacial streams and river water. The results of this study have important implications for policymakers, regulators, and practitioners involved in water and environmental management across CPEC.

Cyanotoxins, produced from cyanobacteria-dominated harmful algal blooms (cHABs), pose a threat to ecosystems, as well as drinking water systems. Disinfection via chlorine is the last step in a conventional drinking water treatment plant (DWTP) to remove any extracellular toxins present in the water. This research investigated the impact of pH on the oxidation of different saxitoxin (STX) and anatoxin-a (ANTX-a) concentrations in the post-filtration water collected from two DWTPs. STX degradation was the most efficient at higher pH levels. For instance, pH 6 resulted in 13–43% degradation and pH 9 resulted in 56–74% degradation of STX. The presence of microcystin-LR (MC-LR) did not significantly inhibit the removal of STX, with STX removal (at pH 6–8) higher than when MC-LR was not present. A dose of 1.8 mg/L chlorine and 235-min contact achieved 38% removal of ANTX-a while the dose of 3.2 mg/L chlorine and the contact time of 118 min removed 75% of ANTX-a at pH 6.

This study aims to investigate the wastewater treatment process and assess the industrial wastewater quality before and after being treated by effluent treatment plants (ETPs) of steel-galvanizing industries located in Mirsharai, Sitakunda, Karnaphuli, and Kalurghat industrial areas of Chattogram, Bangladesh. Wastewater samples were collected from six steel-galvanizing industries during the dry season and monsoon season. The water quality was evaluated based on five physiсochemical parameters, namely pH, dissolved oxygen (DO), biological oxygen demand (BOD₅), chemical oxygen demand (COD), total dissolved solids (TDS), as well as the concentration of heavy metals including Fe, Cu, Cr, Ni, and Cd. The measured data were compared with the national and international standards established for ensuring water safety. It was observed that steel plants generate complex wastewater rich in highly dissolved solids and heavy metal ions. Although pH, BOD₅, and COD values were within acceptable ranges in these industries, high TDS values were observed. The Fe concentration of discharged stream areas ranged from 0.992 to 16.89 mg/L, exceeding the guideline limits. Additionally, the Cr concentration in both the inlet and outlet exhibited high concentrations, surpassing the standard limits, particularly those set by the United States Environmental Protection Agency (US EPA). Thus, steel-galvanizing industries are likely contributing to water pollution through the discharge of wastewater, particularly in terms of Fe and Cr. The efficiency of ETPs varied for different metals. Furthermore, this study highlighted the importance of the effective design of ETPs to mitigate potential pollution and promote sustainable practices.

Changes in the hydrochemical regime of a small river due to anthropogenic load lead to a deterioration in water quality. Pollution of water bodies can affect the volume of production in the fisheries industry. Therefore, a pressing issue for modern fisheries is the continuous monitoring and comprehensive ecological assessment of the quality of surface waters. The study aims to investigate the water quality index (WQI) for fish farming in the Umanka River within the city limits of Uman. As a typical urban river, Umanka experiences the influence of slow water flow, constant discharge of polluted water, ecological degradation, and weak self-purification. Therefore, the need to study and improve the water quality of the Umanka River is quite evident. WQIs are calculated based on the results of analytical measurements of hydrochemical properties of water, such as dissolved oxygen, pH, total (bicarbonate) alkalinity, total mineralization, nitrates, nitrites, ammonium nitrogen, etc. Confirmation of a moderate increase in the concentration of ion composition indicators in the water section studied after the city of Uman is provided by the results of WQI calculations for fish farming during 2021 and 2022 for the analyzed water samples in the direction of the Umanka River flow. Judging by the QWI values for fisheries purposes in 2021, waters from sampling points 1–5 are characterized as “Satisfactory,” with the exceptions being points 6 as “Good” and 7 as “Very Poor.” In 2022, water from the study area in the city of Uman (points 1 and 2) is characterized as “Good,” while the others (points 3–7) are considered “Satisfactory.” Thus, there is an observed deterioration in water quality for fish farming in the research area after the city of Uman.

Karst groundwater is the main water supply source for human consumption and living, and it is important to study the karst groundwater resources to ensure people’s water supply needs. In this study, the northern part of the Baiquan spring area in Hebei Province was taken as a research object. Based on the hydrogeochemical approach, the characteristics and mechanism of seasonal variations of karst groundwater in the area were studied, and the groundwater quality was evaluated. This paper mainly uses multivariate statistics, the Piper trilinear diagram, the ion ratio coefficient, and the water quality index (WQI) as water quality assessment methods. The sequence of the main ion abundance is as follows: Ca²⁺ > Mg²⁺ > Na⁺ > K⁺, ({text{HCO}}_{3}^{ - }) > ({text{SO}}_{4}^{{2 - }}) > Cl^–, and the ion content showed a downward trend from the dry season to the wet season. The hydrochemical type in the dry season has changed compared with that in the wet season. The rate of carbonate rock dissolving in most of the study area waters in the wet season was higher than in the dry season. WQI calculation results show that most of the groundwater belongs to class II water quality, and the water quality in the wet season is better than that in the dry season. Studying different seasonal changes in groundwater chemistry can provide a reference for an in-depth understanding of karst groundwater chemistry characteristics and water resources protection in the spring area.

The effect of the flint mineral on water quality has been studied by biotesting on invertebrate test organisms, such as daphnia (Daphnia magna) and ceriodaphnia (Ceriodaphnia affinis). It has been shown that infusion on flint reduces the acute and chronic toxicity of tap water and increases the reproducibility of test organisms in an artificially prepared simulator. In flint treated water, an increase in the number of test crustacean organisms approaches the reference values for water from natural reservoirs. The adaptation of test organisms to an aqueous medium and their reproduction are immediately related with the physicochemical properties of water. It has been proven that flint neutralizes the negative effect of water toxicity on the functional state of crustaceans.

A novel study was undertaken for cleaning the wastewater from the paint industry by using the combinations of carbon nanoparticles produced from waste material using different methods and TiO₂ nanoparticles. Carbon nanoparticles were produced from sugarcane bagasse (a waste material) by using three different methods, namely charring in a muffle furnace (C₁), heating in the air (C₂), and treating with sulfuric acid (C₃). Atomic force microscopy demonstrated the smaller size of C₂ and C₃ nanoparticles as compared to C₁. Further, Raman spectroscopy displayed fewer defects in C₁ nanoparticles than in C₂ and C₃ but better graphene structure in C₂. Fourier-transform infrared (FTIR) spectroscopy study revealed the degraded structure of carbon nanoparticles prepared by using sulfuric acid (C₃) with more functional groups than C₁ and C₂. A comparative study using UV-visible spectroscopy showed that the sulfuric acid-treated carbon nanomaterials (C₃) were more efficient in removing the contaminants from wastewater from the paint industry because of their small size and functional groups. When carbon nanoparticles were used in the combinations with TiO₂ nanoparticles, study showed that the combination of C₃ with 10% by wt TiO₂ nanoparticles were the best for clearing wastewater. Mechanisms are proposed for the synthesis of TiO₂ nanoparticles and their role along with carbon nanoparticles (C₃) for the removal of contamination from wastewater.

Nickel ion imprinted polymer (Ni-IIP) was prepared using microwave-assisted surface imprinting technique with Ni²⁺ as the template, salicylaldehyde-ethylenediamine Schiff base as functional monomers, ethylene glycol dimethacrylate as a crosslinking agent and alkylated silica gel as a carrier. Fourier transform infrared spectroscopy (FTIR) was used to characterize Ni-IIP, which confirmed the successful synthesis of the polymer. Scanning electron microscopy (SEM) was used to compare the surface morphology of Ni-IIP to non-imprinted polymer (NIP). The SEM analysis found that Ni-IIP had many holes on its surface and abundant spherule structures after elution, while NIP only had a few irregular holes on its surface. The adsorption performance of IIP was studied under different conditions, including pH, temperature, and initial concentration of Ni. The experimental results showed that the maximum adsorption capacity of IIP for Ni was 24.23 mg g^–1 at pH 8, temperature of 30°C, adsorption time of 40 min, and initial concentration of Ni of 30 mg L^–1. The pseudo-second-order kinetic equation could better describe the whole adsorption process, suggesting that chemical adsorption mainly controlled the adsorption process of nickel ions. The Langmuir adsorption isotherm model showed a high linear relationship, and the theoretical adsorption capacity was closer to the actual adsorption capacity, indicating that the adsorption of nickel ions by IIP and NIP occurred in a single layer. Selective experiments showed that IIP had specific selectivity for nickel ions compared with Cu²⁺, Zn²⁺, and Cd²⁺. The results obtained from the analysis of regeneration and practical application demonstrate the promising potential of the prepared Ni-IIP for the efficient removal of nickel pollutants from water sources. These findings provide a new approach to the removal of Ni from wastewater.

The state-of-the-art in the physical chemistry of atmospheric aerosols is considered. Special emphasis is laid on the sources and possible mechanisms of their formation and their composition. It is pointed out that contaminants of anthropogenic origin in lower atmosphere layers provoke global climatic changes. The positive and negative effects of aerosols on the environment are studied. The need for a theory of aerosols with the purpose of solving the urgent environmental problems is substantiated. Aerosols may both good and harmful for a person. Artificial aerosols are used to treat people and animals, provoke rain, prevent hail, etc. The solution of many problems, even those crucial for the future of human existence on the Earth, depend on the successful development of aerosol theory. It is shown that the effect of aerosols on the climate is now incorrectly estimated primarily due to inaccuracy in studying the formation of atmospheric aerosols and a lack of information about their physicochemical properties.