Mahtab Ahmad

In this study, Parthenium hysterophorus biomass was converted into biochar adsorbents (PTC300, PTC500, and PTC700) through pyrolysis at 300°C, 500°C, and 700°C, respectively. These biochars were subsequently evaluated for their efficacy in removing Cd(II) from industrial wastewater. The adsorption mechanisms were investigated using kinetic and isothermal models and post‐adsorption characterization of biochars with the help of Fourier‐transform infrared spectroscopy, scanning electron microscopy, and energy‐dispersive x‐ray spectroscopy. The PTC500 and PTC700 exhibited high aromaticity, hydrophobicity, porosity, and BET surface area (65.9 and 77.8 m ² /g, respectively) because of high pyrolytic temperatures. Among the synthesized adsorbents, PTC500 exhibited the highest adsorption capacity (41.28 mg/g) as predicted by the Langmuir isotherm model in the batch adsorption study. From the real industrial wastewater, PTC500 resulted in 95% removal of Cd(II). The adsorption process followed the Langmuir isotherm, suggesting monolayer adsorption. Additionally, the pseudo‐first‐order kinetic model indicated that physical adsorption predominated on the surface of the biochars. The unique properties of the biochars, such as their porous structure, diverse surface functional groups, and high concentration of base cations, played a critical role in the effective adsorption of Cd(II). Key mechanisms involved in the adsorption process included surface complexation, Cd–π interactions, ion exchange, and precipitation.

Groundwater constitutes the primary source of liquid freshwater on Earth and is essential for ecosystems, agriculture, and human consumption. However, rising demand, urbanization, and climate change have intensified groundwater depletion, particularly in semi-arid regions. Therefore, assessing groundwater recharge zones is essential for sustainable water resource management in vulnerable areas such as Dera Ismail Khan, Pakistan. This study aims to delineate groundwater potential zones (GWPZs), using an integrated approach combining the Geographic Information System (GIS), remote sensing (RS), and the analytical hierarchy process (AHP). Twelve factors were identified in a study conducted using GIS-based AHP to determine the groundwater recharge zones in the region. These include land use/land cover (LULC), rainfall, drainage density, soil type, slope, road density, water table depth, and remote sensing indices such as Normalized Difference Vegetation Index (NDVI), Normalized Difference Built-up Index (NDBI), Moisture Stress Index (MSI), Worldview Water Index (WVWI), and Land Surface Temperature (LST). The results show that 17.52% and 2.03% of the area have “good” and “very good” potential for groundwater recharge, respectively, while 48.63% of the area has “moderate” potential. Furthermore, gentle slopes (0–2.471°), high drainage density, shallow water depths (20–94 m), and densely vegetated areas (with a high NDVI) are considered important influencing factors for groundwater recharge. Conversely, areas with steep slopes, high temperatures, and dense built-up areas showed “poor” potential for recharge. This approach demonstrates the effectiveness of integrating advanced remote sensing indices with the AHP model in a semi-arid context, validated through high-accuracy field data (Kappa = 0.93). This methodology offers a cost-effective decision support tool for sustainable groundwater planning in similar environments.

The effect of trivalent metal-modified biochar on the stability and mitigation of fluoride ions (F^-) in contaminated soils remains largely unexplored, despite biochar’s extensive application in F^--contaminated soil. The mineral metal-modified biochar has the potential to serve as an efficient solution for soil contaminated with F^-. In this study, pristine-pinecone biochar (P-BC) and AlCl₃-modified pinecone biochar (A-BC) were synthesized and then utilized to remediate the soil that had been contaminated with F^-. Both P-BC and A-BC efficiently immobilized F^- within the contaminated soil. Further examinations through sequential extraction procedure and subsequent analysis using scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and elemental dot mapping demonstrated a transformation of F^- into a more stable state by A-BC treatment of the contaminated soil. This implies that A-BC may possess the capacity to function as an efficient ameliorant for immobilizing F^- within the soil.

Extreme climates and the unpredictability of the weather are significant obstacles to agricultural productivity. This study is the first attempt to explore the capacity of nanobonechar (NBC) for promoting climate-smart agriculture. A pot experiment was performed on maize (Zea mays L.) under a deficit irrigation system (40, 70, and 100% irrigation rates) using different soil application rates of the NBC (0, 0.5, 1, and 2% wt/wt). Additionally, the CO₂–C efflux rate and cumulative CO₂–C were measured in an incubation experiment. The results indicated the best performance of the 1% NBC treatment under a 70% irrigation rate in terms of the fresh and dry weights of maize plants. Total PO₄³⁻ and Ca²⁺ were significantly higher in the plants grown in the NBC-amended soil as compared to the control, showing a gradual increase with an increase in the NBC application rate. The improved productivity of maize plants under a deficit irrigation system was associated with enhanced water-holding capacity, organic matter, and bioavailability of cations (Ca²⁺, K⁺, and Na⁺) and anions (PO₄³⁻ and NO₃⁻) in the soils amended with NBC. The CO₂–C efflux rate and cumulative CO₂–C emissions remain higher in the NBC-amended soil than in the un-amended soil, pertaining to the high contents of soil organic matter emanating from the NBC. We conclude that NBC could potentially be used as a soil amendment for promoting maize growth under a water stress condition.