Sustainable Waste Management, Environmental Science & Climate Change

Title: Carbon materials facilitating smarter agricultural waste management for advanced environmental sustainability: 3D—0D

Abstract: Utilization of agricultural wastes for value-added products is essential for achieving sustainable development goals and carbon neutrality. The annual production of agricultural wastes in China is about 3.9 billion tons, with crop straw accounting for 19%, and livestock and poultry manure accounting for 67%. Currently, biological methods such as anaerobic digestion and humification are the primary approaches for agricultural resource utilization, leading to the production of biogas and fertilizer. However, these methods are inefficient, and often encounter failure owing to the physiological limitations of the microbes involved. Carbon materials, ranging from 3-dimentional (3-D) to zero-dimensional (0-D), can act as enhancers of the microbial biochemical processes. In our study, biochar, the 3-D carbon material produced from chicken manure, increased the methane content (70%) of biogas while reducing the carbon dioxide and hydrogen sulfide contents. Biochar prepared from lignin-based raw materials displayed suitable physico-chemical properties that could enrich syntrophic fermentation bacteria, promoting direct interspecies electron transfer (DIET) and increased methane production. In another of our study it was seen that magnetic biochar loaded with MnO₂ increased cumulative methane production from kitchen waste by 24.32%. The redox capability of magnetic biochar enhanced the capacitance and promoted microbial enrichment and their electron transfer processes. In a separate study we observed that introducing biogas residue biochar into pig manure compost helped reduce NH₃ emissions while storing more nitrogen in the compost matrix. Carbon quantum dots (CQDs) are a type of quasi-zero-dimensional carbon nanomaterial with remarkable fluorescence properties. In one of our more recent studies, we developed nitrogen-doped CQDs that behaved like n-type semiconductors, increasing cumulative methane yield by 1.9 times by enhancing metabolic pathways for methane production and coenzyme F₄₂₀ biosynthesis. The technologies developed by our lab have been successfully applied in multiple locations and scenarios across China, and have received wide-spread attention and coverage from mainstream media. At present we are focused on deciphering the intrinsic mechanistic pathways such that they can be stimulated for further enhancement of the functionality of carbon materials for smarter agricultural waste management for advanced environmental sustainability

Title: Surface functionalization of polypropylene with graphene oxide (GO) from
pyrolysed tire waste: toward breathable and antibacterial biointerfaces

Abstract: The development of sustainable antibacterial textiles with strong interfacial functionality
remains a challenge. This study presents a sustainable approach to fabricating
antibacterial nonwoven polypropylene (PP) fabrics
functionalized with graphene oxide (GO) synthesized from recovered carbon black (rCB)
derived from pyrolyzed waste tires, offering a cost-effective alternative to graphite-based
GO. An alkaline-oxidative pretreatment was applied to improve GO adhesion on the
hydrophobic PP surface. Raman spectroscopy revealed an ID/IG ratio of 0.82, indicating a
high oxidation degree. FTIR and FESEM-EDX confirmed chemical interactions and
uniform GO dispersion. The functionalized PP-GO fabrics demonstrated antibacterial
activity with inhibition zones of 11.6 +- 1.85 mm against Escherichia coli and 11.5 +- 1.37
mm against Pseudomonas aeruginosa, showing 25–35 % enhancement compared to
untreated fabrics. Air permeability (190.07 mm/s) and porosity (75.69 %) were maintained
within wearable comfort standards. This work introduces a novel waste-to-functional textile
platform through interface engineering, enabling durable antibacterial performance and
contributing to sustainable and breathable protective fabrics for healthcare use.

Title: Market Structure and Spatial Dynamics of Sugarcane-Based Bioelectricity Supply in Brazil: Empirical Evidence for a Circular Economy

Abstract: The integration of renewable energy systems with waste management has become a
strategic pillar for advancing the circular economy, environmental sustainability, and
evidence-based decision-making by policy-makers aimed at mitigating greenhouse gas
emissions. In Brazil, sugarcane-based bioelectricity stands out as one of the most
consolidated waste-to-energy pathways, converting agro-industrial residues from the sugar
and ethanol industry into renewable electricity. Despite its growing relevance in the
national energy matrix, the literature still lacks integrated analyses that jointly address
market structure, supply concentration, spatial dynamics, and the spatio-temporal
persistence of production clusters, which are critical for designing sustainable and inclusive
energy and waste policies. This study examines the market structure and spatial dynamics of sugarcane-based bioelectricity supply in Brazil, providing empirical evidence to support integrated
renewable energy and waste management planning under a circular economy and
sustainability perspective. The analysis covers the period from 2000 to 2024 and is based
on official data on granted capacity and the geographic location of operating plants.
Methodologically, the study combines three complementary analytical approaches. First,
supply concentration and market structure are assessed using classical Industrial
Organization indicators, including the Concentration Ratio (CRk), the Herfindahl–
Hirschman Index (HHI), the Theil Entropy Index, the Comprehensive Concentration Index
(CCI), and the Hall–Tideman Index (HTI), applied at different territorial scales. These
indicators allow a detailed characterization of concentration levels, market
competitiveness, and the distribution of installed capacity across regions and production
hubs. Second, Exploratory Spatial Data Analysis (ESDA) is employed through Global Moran’s I,
Local Indicators of Spatial Association (LISA), and bivariate spatial autocorrelation
techniques to identify spatial dependence, regional clusters of high and low generation
capacity, and associations between bioelectricity supply and human development
indicators. Third, spatial and spatio-temporal Scan statistics are applied to detect
statistically significant and persistent clusters over time, enabling the identification of
structural hotspots and long-term spatial trajectories in the expansion of sugarcane
bioelectricity. The results reveal a highly concentrated market structure at national and regional levels,
with a strong dominance of the Center-South regions of Brazil, while more disaggregated
territorial scales exhibit relatively higher dispersion and competitiveness. ESDA results
indicate the consolidation of high-capacity clusters in regions with higher socioeconomic
development, whereas extensive areas in the North and Northeast remain weakly
integrated into waste-to-energy systems. Scan statistics confirm the spatio-temporal
persistence of major generation hubs, reinforcing the existence of path-dependent
structural and locational factors shaping the diffusion of bioelectricity. Bivariate analysis
further shows a positive spatial association between installed capacity and human
development levels, particularly after 2010. Overall, the findings indicate that while sugarcane-based bioelectricity effectively supports waste valorization, greenhouse gas mitigation, and resource efficiency, its territorial expansion remains uneven. The integration of Industrial Organization concentration
indices, spatial analysis, and Scan statistics provides a robust analytical framework to

Title: Structural Vegetation Protection provided by Leafless Caatinga During the Dry Season in the Brazilian Semi-Arid region, a climate change spot

Abstract: The Caatinga, as nominated the Brazilian shrub during the dry season to survive temporally
lost its leaves to save water, remaining physiologically actives. During the dry season, this plant
has only stems, branches, and roots for eight to nine months. What protection during the dry
season promotes the deciduous plants from Caatinga to soil and environment? Do stems and
branches offer environmental coverage and protection during initial rainfall events? Searching
for an answer to these questions: sixteen simulated rains during the Brazilian semi-arid dry season
evaluated the structural effects of stems, branches and litter from Caatinga, as well as bare soil.
The isolated stems and branches, as well as those combined with the litter effect, reduced flow
velocity and increased hydraulic resistance. Structural vegetative elements from Caatinga, such
as litter (fallen leaves on the soil surface), stems, and branches, produced hydraulic resistance,
increasing environmental protection against overland flow through transitions from bare soil to
litter alone, stems alone, and stems and branches with a litter layer. This progressive increase in
surface roughness protects the soil and environment from rainfall erosivity, overland flow
hydraulic action, and inter-rill erosion. Therefore, even under the stress of the dry season, through
its structural adaptations, the Caatinga, as part of the semi-arid ecosystem, remains ecologically,
physiologically, and hydrologically functional.