Frontiers in Water and Environment

Recent Developments of Nanocomposite Adsorbents for Removal of Heavy Metals from Water: A Review

Asma Siddqua — 2025-03-10

Recently, there has been an increase in interest in nanotechnology to improve water quality due to its large surface area and high efficiency. This review aimed to study the recently developed nanocomposite adsorbents for removing heavy metals from water. The majority of the nanocomposites achieved maximum adsorption capacity with a moderate pH (5-9), a minimum adsorbent dosage (0.1-2 g/L), and 20-60 min for achieving equilibrium and could be used for 4-6 cycles, suggesting economic feasibility. The study showed that the physisorption occurred at a low mean free energy of surface adsorption and, in contrast, chemisorption occurred at a higher value, and most of the adsorption processes followed the pseudo-2nd-order kinetics reaction. A thermodynamic study of the adsorbents illustrated the spontaneous nature and increase of randomness during the adsorption process. A comparative analysis of the nanocomposites revealed the selectivity of iron oxide nanocomposites towards the removal of Pb(II) ions; polythiophene-modified chitosan/magnetite nanocomposites could remove 100% of Hg(II) ions. The nanocomposite adsorbents face challenges in large-scale production, regeneration, and economic suitability. The study provides valuable insights for future research on the green synthesis of nanocomposite adsorbents for heavy metal removal processes.

Impacts of Rainfall Variability on Water Quality Parameters in the Setiu River, Malaysia

Siti Nurhidayu Abu Bakar — 2025-03-10

Water quality status serves as an essential indicator of the river’s health and its capacity for beneficial uses, reflecting changes in physical, chemical, and biological factors that are often sensitive to both natural and anthropogenic influences. The Setiu River in Terengganu faces an increasingly critical challenge in understanding the complex relationship between rainfall patterns and water quality dynamics. This study chooses the Setiu River as a case study and aims to address three primary objectives to gain insights into these dynamics: firstly, to examine the relationship between rainfall and water quality across wet and dry seasons; secondly, to analyze seasonal variations in specific water quality parameters in response to differing rainfall patterns; and thirdly, to investigate the relationship between water quality data at upstream and downstream monitoring stations. Rainfall data from the Department of Irrigation and Drainage (DID) and water quality parameter data from the Department of Environment (DOE) for Kampung Buloh and Water Intake Kg Besut stations were analyzed. The results reveal distinct seasonal differences, with correlation analyses showing a significant negative relationship between rainfall and pH during dry seasons, suggesting a dilution effect, and positive correlations between rainfall and NH₃-N, indicating increased ammoniacal nitrogen levels. These findings imply that rainfall exerts substantial seasonal influence on key water quality parameters, with potential implications for ecosystem health, especially under prolonged dry or wet conditions. Nevertheless, a longer duration and more frequent data collection intervals are necessary to capture a comprehensive representation of rainfall’s overall effects on river water quality. Future studies should integrate discharge analysis with water quality parameters, which could provide a more detailed understanding of the interactions between rainfall, river flow, and pollution transport. This study contributes valuable knowledge to the broader discourse on river water management, emphasizing the importance of rainfall considerations in riverine health assessments.

Investigating the Presence and Distribution of Microplastics in Wastewater Treatment Plants Systems

Hanie Wardah Marup — 2025-03-10

Microplastic is a highly concerning emerging contaminant with the significant increase of municipal waste along with the elevating growth of population. Wastewater is one of the main routes contributing to the persistent microplastics presence in the environment since it originates from domestic, industrial, and even agricultural wastewater. These facilities are increasingly identified as potential contributors to the release of microplastics (MPs) into the environment. This study aims to examine the occurrence and distributions of MPs in both the influent and effluent of two districts sewage treatment plant (STP) in Kota Kinabalu (UMS STP) and regional sewage treatment plant Penampang (RSTP) Sabah Malaysia. The results showed that the abundance of MPs in UMS STP was higher in both influents and effluents than RSTP. The average size of MPs found varied from 1.0 mm to 125 µm being the most abundant. Microplastics 2.0 mm is higher in influents, while effluents exhibit higher concentrations of smaller particles (63 µm). In terms of microplastic morphology, fragments were identified as the most predominant shape in the sampled materials from both sewage treatment plants (STPs), whereas microplastic beads were the least frequently detected. The distribution of colours across the influent and effluent samples was consistent, with a variety of colours identified, though green, blue, and red predominated. Polymer analysis revealed a diverse array of microplastic types present in the samples, including polypropylene (PP), nylon (PA), and polyethylene terephthalate (PET/PETE), indicating a variety of sources and characteristics of the microplastics entering the treatment systems. These polymer types were found in both influent and effluent, suggesting that certain microplastics may persist through the treatment process. Overall, this study offers a comprehensive analysis of the physical and chemical properties of microplastics in wastewater treatment systems, providing valuable insights into their distribution, persistence, and the potential implications for the fate of microplastics within wastewater treatment processes. The findings contribute to a better understanding of microplastic behavior, highlighting key factors influencing their occurrence and removal efficiency in sewage treatment plants.

Investigation of Physicochemical Properties of Tabin Mud Volcano

Habib Musa Mohamad — 2025-03-10

Volcano mud is a rare phenomenon found in specific areas, such as Lipad, Sabah, Malaysia, characterized by superficial vents that expel mud and gas flows. This process influences topography, soil properties, ecosystems, and landscapes. Understanding the chemical composition and physical properties of this mud is crucial for assessing rare-earth elements, fluid characteristics, and environmental impacts. In this study, the mud's physicochemical properties were analyzed, revealing a pH of 7, moisture content of 25.17%, and a particle size distribution of 6368 d.nm. Geochemical analysis via Energy Dispersive X-Ray (EDX) identified elements like Oxygen, Silica, Aluminum, Iron, and others, with O and Si being dominant. Rare clinochlore minerals were also detected using X-Ray Diffraction (XRD). The mud exhibited a negative surface charge of -26.5 mV and a unique morphology described as flakes and brittle, differing from typical soil structures as observed by Field Emission Scanning Electron Microscopy (FESEM). Additionally, a high nitrogen compound content of 2.31% was detected, indicating potential gas release of nitrogen and carbon dioxide.