Journal of Sustainable Environment

Mysterious Effect of Temperature on Conductivity of Calcium Hydroxide

Atya Hassan, Syed Azhar Ali, Syed Madhi Haider — Wed, 31 Dec 2025 00:00:00 +0000

The Solubility of Ca(OH)₂ aqueous solution was investigated at certain temperatures that were 30±1ºC, 60±1ºC, 70±1ºC and 80±1ºC. The occult results about solubility were obtained via using conductometry analysis. With the help of specific conductance (Ƙ) activation energy (ε), frequency factor (A) of Ca(OH)₂solution calculated. The thermodynamic properties of Ca(OH)₂ also examined. Gibbs free energy (ΔG), entropy (ΔS) and enthalpy (ΔH) of Ca(OH)₂ determined at different temperatures. Solubility product (K_sp) also estimated via equivalence point. Apart this, Ionic strength (μ_i), activity coefficient (f_i) as well as activity (a_i) of Ca(OH)₂ evaluated. Entropy as well as ionic strength of Ca(OH)₂ratified that the solubility of calcium hydroxide inversely proportional to temperature

Plantation-Driven Watershed Degradation and Intergenerational Erosion of Traditional Ecological Knowledge in the Chittagong Hill Tracts, Bangladesh: A Multi-Ethnic Comparative Study

Ruth Shraboni Joydhor — Wed, 31 Dec 2025 00:00:00 +0000

The Chittagong Hill Tracts (CHT) of Bangladesh harbours at least 13 indigenous communities whose livelihoods, cultural identities, and ecological knowledge systems are intimately embedded in a forested hill landscape now undergoing rapid transformation. This study investigates a theoretically proposed but empirically untested causal chain: that plantation expansion reduces spring water availability, which in turn severs the ecological contexts of traditional ecological knowledge (TEK) transmission, driving measurable intergenerational knowledge loss. Drawing on a mixed-methods design comprising multi-temporal Landsat LULC analysis (1993–2023), a structured household survey (n=600) using an adapted TEK Transmission Index (TEK-TI), and qualitative life-history interviews (n=60) across five ethnic communities (Chakma, Marma, Tripura, Mro, and Khasi) in all three CHT districts, the study tests this structural mechanism using piecewise structural equation modelling (piecewiseSEM) with bootstrap mediation analysis. Results reveal that dense forest cover declined by 6.23% and settlement/plantation area increased by 10.34% between 1993 and 2023, with rubber monoculture a primary driver. Spring Water Availability Index (SWAI) scores declined significantly across all communities, with communities in high-plantation-exposure zones reporting 47% lower SWAI than low-exposure communities. The intergenerational TEK-TI gap averaged 28.4 points across communities, with the Mro community exhibiting the highest gap. Piecewise SEM confirms that watershed degradation fully mediates the effect of plantation expansion on TEK erosion (indirect path coefficient: β = −0.41, 95% CI [−0.56, −0.27], p < 0.001), with the direct effect rendered non-significant once SWAI is controlled. Multi-group invariance testing reveals significant ethnic moderation, with land tenure security and cultural transmission institution strength moderating the plantation-watershed-TEK pathway. These findings provide the first empirical quantification of hydrologically-mediated TEK erosion, with direct implications for CHT forest governance, indigenous land rights policy, and the integration of biocultural diversity conservation into the Bangladesh Delta Plan 2100.

Chemical oxo-precipitation method: A Sustainable approach towards boron wastewater treatment

Rabia Khatoon, Asghar Ali Ghoto, Majid Ali — Wed, 31 Dec 2025 00:00:00 +0000

High boron levels in water or wastewater poses an environmental threat. The extraction of boron from water or wastewater is crucial for environmental sustainability. There are various techniques for the removal and recovery of boron from wastewater, such as adsorption, membrane technology, and chemical precipitation. This review presents a concise evaluation of different technologies for boron removal. From the analysis, it is concluded that the chemical oxo precipitation method has several advantages, such as that it produces less volume of sludge and works at room temperature at alkaline pH, which reduces energy cost. However, barium salt chemical oxo precipitation may produce some toxic waste, but these effects can be overcome with the integration of technologies like chemical oxo precipitation with fluidized bed crystallization. Moreover, the method did not require solvent and costly membranes. Therefore, future studies may investigate the integration of technologies with chemical oxo precipitation, regeneration and recycling of precipitant, industrial application, and extensive techno chemical analysis for the green environment.

Extraction and Application of Natural Pigments from Plant Sources as Sustainable Alternatives to Synthetic Dyes.

hasan muneer, Bisma Zakir Hussain, Lumat Un Noor, Shafaq Aiyaz Hassan — Wed, 31 Dec 2025 00:00:00 +0000

Colors are necessary and extensively used items. Man has made colors synthetically which are used in different industries world-wide, causing damage to life and environment. Natural dyes are biodegradable and are beneficial as they contain antioxidants, vitamins etc. So, the world is trying hard to shift from chemical dyes towards naturally made.

The aim is to show potential of natural extracts in dyeing of bioplastic, soap, lip balm, and cotton cloth. It promotes the use of natural dyes instead of chemical ones, which cause health problems, persist in environment and release toxic elements. This study shows that natural colors can be used instead of chemicals across multiple applications. Bioplastic is made by gelatinization process, for soap lye solution is made, for lip balm the sample was heated and mixed with different ingredients until it homogenizes, and for dyeing cotton, scouring and mordanting techniques were used. All these products were made under specific lab procedures. Bioplastic was flexible (moldable), and smooth in texture, cotton cloths gained bright colors and did not remove on washing (due to mordanting). The lip balm was smooth, creamy, semi-solid, the soap was firm and smooth in texture. Products were dyed successfully with beetroot, spinach and turmeric extracts. Bright, safe, and biodegradable colorants were yielded and successfully applied. Overall, it proved that by using natural plant-based colors/dyes, it can contribute at large scale to a sustainable world by replacing synthetic-chemical dyes used in industries and at other scales.

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Physical Characterization and Resource-Recovery Potential of Municipal Solid Waste at Transfer Stations and a Landfill in Karachi, Pakistan

Osama Zulqurnain, Farooq Ali Khan — Wed, 31 Dec 2025 00:00:00 +0000

Municipal solid waste (MSW) characterization is needed to select recovery and disposal options that reflect local waste streams. This study characterized 20 MSW samples from three garbage transfer stations and Jam Chakro disposal site in Karachi, Pakistan, using manual sorting based on ASTM D5231-92. Five samples were analyzed at each site; sample masses ranged from 92 to 105 kg, with 1,988 kg characterized overall. Pooled composition was dominated by other inorganics/non-combustibles (36.3%), plastic (19.7%), food waste (13.4%), other organics/combustibles (12.0%), yard waste (7.6%), and diapers/sanitary products (6.7%). Sample-level analysis showed significant between-site differences in food waste, corrugated material, and other inorganics after false-discovery-rate adjustment. Film represented 95.5% of the plastic fraction. Results support source segregation and targeted recovery, while transfer-to-landfill differences cannot be attributed solely to informal scavenging because waste loads were not paired.