Journal of Environmental & Earth Sciences

Biomass as a Green Source of Dopants: A Review on In-Situ Synthesis of P-N Co-Doped ZnO for Photocatalytic Dye Degradation

2025-11-24T15:23:43+08:00

Synthetic dyes, particularly azo dyes, pose significant environmental and health risks due to their persistence, toxicity, and potential carcinogenicity. Zinc oxide (ZnO) is a promising photocatalyst for wastewater remediation, but its wide bandgap and rapid charge recombination limit its practical efficacy. Furthermore, conventional doping methods often rely on hazardous chemical precursors, undermining the sustainability of the overall approach. This review introduces a novel and sustainable paradigm: the utilization of biomass-derived precursors as green reagents for the in-situ synthesis and simultaneous phosphorus-nitrogen (P-N) co-doping of ZnO nanoparticles. We critically analyze how the intrinsic biochemical composition of biomass, rich in P, N, and other heteroatoms, facilitates this one-pot, eco-friendly functionalization. This integrated strategy merges the performance enhancement offered by advanced co-doping, such as extended visible-light absorption and suppressed charge recombination, with the core principles of green chemistry and circular economy. It offers a dual benefit: creating highly effective photocatalysts for the degradation of persistent pollutants and valorizing abundant agricultural or biological waste streams. Our comprehensive evaluation goes beyond description to critically assess the underlying mechanisms, comparative efficacy, scalability challenges, and future research directions of this emerging field. This review underscores the unique contribution of biomass-mediated synthesis to advancing sustainable nanotechnology for environmental applications.

Rock Discontinuity Extraction from 3D Point Clouds: Application to Identifying Geological Structures in the Miocene–Pliocene Deposits, Japan

2025-12-25T14:06:53+08:00

Evaluating rock mass quality using three-dimensional (3D) point clouds is crucial for discontinuity extraction and is widely applied in various industrial sectors. However, the utilization of this method in geological surveys remains limited. Notable limitations of current research include the scarcity of validation using simple geometric shapes for discontinuity extraction methods, and the lack of studies that target both planar and linear discontinuity. To address these gaps, this study proposes a workflow for identifying discontinuity planes and traces in rock outcrops from photogrammetric 3D modeling, employing the Compass and Facets plugins in the open-source CloudCompare software. Prior to field application, the efficacy of the extraction methods was first evaluated using experimental datasets of a cube and an isosceles triangular prism generated under laboratory-controlled conditions. This validation demonstrated exceptional accuracy, with the dip and dip direction (DDD) of extracted structures consistently within ±2° of the actual values. Following this rigorous laboratory validation, this methodology was applied to a more complex natural rock outcrop (Miocene–Pliocene deposits in Japan), demonstrating its applicability in realistic geological settings for identifying structures. The results showed that the dip and dip direction trends of the extracted bedding planes and faults were consistent with field measurements, achieving a time reduction of approximately 40% compared to traditional methods. In conclusion, through strictly controlled initial verification and subsequent successful application to a complex natural setting, this study confirmed that the proposed workflow can effectively and efficiently extract discontinuous geological structures from point clouds.

Material Selection and Climate Change

2025-06-04T18:13:37+08:00

This paper deals with carbon emissions reduction through building material selection in housing construction using Analytical Hierarchy Process (AHP) method. Drawing on the concept of Sustainable Development in the Environment (SDE), inadequate selection of building materials makes a significant contribution to carbon emissions. The achievability of the goal of SDE is in rethinking Locally Sourced and Recycled Building Materials (LSRBMs) selection decision making, in acknowledging cultural issues, towards the wider industrial use of Recycled Concrete Crushed Block Wall (RCCBW) which is about 66%, in carbon emissions, as good as Air-crete Hollow Block Wall (AHBW). With results derived from questionnaire survey with recruited civil engineers and architects, key sustainability principle indicators influencing the selection of building materials are identified, analysed, grouped and ranked using AHP, a concept of measurement through pairwise comparisons of tangible and intangible factors to derive priority scales in relative terms. This explained 17.27% cut back in carbon emissions for selecting Compressed Stabilized Rammed-Earth Block Wall (CSREBW) instead of AHBW. The lack of informed knowledge in the wider use of RCCBW and CSREDW and in the Ghanaian context towards future reduction in carbon emissions in the housing sector of the construction industry of Ghana. Subsequently, the study yielded the following theoretical, practical and policy implications: A new interpretation of existing building materials; Understanding the impact of building materials’ attributes; In effect, might be beneficial to universities and organizations to come up with training policies that aim to take advantage of the new technology respectively.