This study investigated the potential of plant growth-promoting microorganisms isolated from palm oil sludge. Three bacterial isolates (Bacillus pumilus N1, Bacillus cereus L18, Pseudomonas stutzeri L9) and two fungal isolates (Talaromyces oumae-annae P1, Westerdykella sp. P2) with good plant growth-promoting traits were selected for inclusion in a microbial consortium. The microbial consortium was immobilized onto spent oil palm fiber (OPF) adsorbent. Microbial compatibility and survival were evaluated via culture-based methods and scanning electron microscopy (SEM) analysis. A pot trial was performed with green round Amaranthus sp., involving four different treatments: control (T0), soil with spent OPF adsorbent (T1), soil with microbial-immobilized spent OPF adsorbent (T2) and soil with commercial biochar (T3). Results showed that T2 significantly enhanced plant growth, by increasing dry weight (65

Industrial wastewater sludge represents a significant environmental burden due to the increasing volume generated and the limitations of conventional disposal methods such as landfilling and incineration. As industries seek sustainable and cost-effective waste management alternatives, energy recovery from sludge has emerged as a promising solution. This study investigates the potential of industrial wastewater sludge as an alternative solid fuel by evaluating the physicochemical characteristics of six sludge types collected from different industrial sectors: Beverage Production, Beverage Recycling, Dairy Processing, Flavour Industry, Oleochemical, and Paper Processing. Comprehensive analyses were conducted, including MC determination, proximate analysis, calorific value measurement using bomb calorimetry, thermogravimetric analysis, and heavy metal quantification via Flame Atomic Absorption Spectroscopy. The calorific values ranged from 11.85 to 31.31 kJ/g, with Dairy Processing wastewater sludge recorded the highest average HHV at 31.308 kJ/g, placing it within the typical coal range (26.50–34.63 kJ/g). Meanwhile, Beverage Production, and Oleochemical sludges showed lower energy content than coal but surpassed both charcoal benchmarks (19.09 and 20.09 kJ/g). Proximate analysis revealed high volatile matter and fixed carbon content, further supporting their suitability for thermal energy recovery. However, sludges with high MC, particularly from beverage industries, require pre-treatment for efficient combustion. The study underscores the viability of industrial sludge as a renewable energy source and recommends optimization of treatment processes.

Phase change materials (PCMs) are recognized for their ability to absorb and release substantial latent heat, making them essential for enhancing energy storage density and thermal regulation. Polymeric PCMs have attracted considerable attention owing to their versatility and broad application potential. This systematic review, covering the literature from January 2019 to August 2024, followed the PRISMA methodology to investigate the evolving roles of polymers in PCM systems, including their use as shells, matrices, coatings, and core materials. The classification is based on synthesis techniques, thermal properties, and application areas. Key findings indicated that in situ emulsion polymerization is the most effective method, offering improved thermal stability and uniform encapsulation. Polymers, such as polyethylene glycol and polystyrene, have emerged as dominant materials owing to their favorable thermal properties and compatibility with various PCMs. Additionally, nanocomposite strategies significantly enhance the thermal conductivity and mechanical strength, expanding their applicability in building materials and thermal management systems. This review also addresses existing challenges and outlines future research directions. These insights aim to support innovations in polymeric PCM design and accelerate the development of sustainable energy storage solutions.

Abstract BACKGROUND MgO‐based sorbents offer high theoretical CO 2 capacity but are constrained in practical applications by sluggish sorption kinetics, prolonged induction periods, and poor performance under the low CO 2 concentration typical of flue gas. This study proposes a mild activation strategy to reduce the nucleation barrier for MgCO 3 formation and investigates its effectiveness together with reactor operating conditions using a simulated flue gas stream containing 15% CO 2 . RESULTS The fresh 9 mol% (Li 0.18 Na 0.52 K 0.30 )NO 3 ‐MgO sorbent exhibited slow carbonation kinetics, requiring 74.2 min to reach its peak sorption rate of 0.0423 mmol/g·min and achieving 7.58 mmol/g at 280 °C after 4 h. Activation at 240 °C for 0.5 h shortened the time to peak sorption to 8.1 min, increased the peak sorption rate to 0.0784 mmol/g·min, thereby enhancing the CO 2 uptake to 9.46 mmol/g. Effective regeneration required temperatures above 320 °C, with non‐isothermal operation achieving >90% desorption efficiency at 340 °C. Although activation substantially improved intrinsic sorption kinetics, high CO 2 removal efficiency was only achieved when sufficient gas–solid contact time was provided. At a weight hourly space velocity (WHSV) of 1.7 mL/g·min after sorption at 280 °C for 4 h, the activated sorbent achieved 81.9% CO 2 removal efficiency. The activated sorbent maintained an average CO 2 removal efficiency of 81.35% over 10 cycles, with each sorption cycle lasting for 1.5 h at 280 °C. CONCLUSION Activation improves the intrinsic sorption kinetics, while lowering the WHSV translates these kinetic improvements into high CO 2 removal efficiency. © 2026 Society of Chemical Industry (SCI).

Oversupplying one of the non-renewable essential macronutrients, phosphorus, in the aquaculture industry has given rise to water pollution issues. Hence, recovering phosphorus from aquaculture wastewater is essential to prevent eutrophication in water bodies and to make effective use of the nutrient. Thus far, no one has reported on the utilization of calcined eggshell as an adsorbent to recover phosphate from actual aquaculture wastewater. Therefore, this study focuses on a sustainable approach in recovering phosphorus through the adsorption process using calcined eggshell (CES) as adsorbent. The effect of influent flow rate (10-50 mL) and dosage of adsorbent (0.2-1.8 g) was assessed via breakthrough curves. The breakthrough curve behaviour was determined through linear and non-linear models of Adam-Bohart, Thomas, and Yoon-Nelson model. The phytotoxicity of the spent adsorbents was assessed using the germination index. The optimized adsorption capacity was recorded as 21.2 mg/g of phosphate under a wastewater flow rate of 28 mL/min and using 1.17 g of CES. The ANOVA analysis (R2 = 0.9766) proved that the experimental and predicted values significantly agree with each other. The non-linear Yoon-Nelson model was found to be the best model to demonstrate the column behaviour in this study with the significant value of the correlation coefficient. Only mild phytotoxicity effect was observed using spent CES. This study provides a sustainable solution for recovering phosphorus from aquaculture wastewater and the possible reutilization of the spent CES as a soil conditioner.

Bismuth-based photocatalysts are valued for their layered structures and efficiency in degrading pollutants like PPCPs and POPs, while zinc ferrite (ZnFe2O4) offers visible-light activity, stability, and magnetic recovery. Here, ZnFe2O4/Bi2O2CO3 (ZB) composites with varied ratios were synthesized and evaluated for degrading bisphenol A (BPA), a common endocrine-disrupting contaminant in plastics and resins. XRD and HRTEM confirmed the coexistence of ZnFe2O4 and Bi2O2CO3 phases with distinct lattice planes, verifying heterojunction formation. SEM imaging combined with EDX mapping showed uniform anchoring of ZnFe2O4 nanoparticles (similar to 200 nm) onto Bi2O2CO3 nanosheets, while XPS analysis validated the expected oxidation states of Bi3+, Zn2+, and Fe3+ together with surface oxygen species. UV-vis DRS showed enhanced light absorption and a red-shifted edge in the composites compared to pristine Bi2O2CO3. The electrochemical impedance spectroscopy results demonstrated a substantial decrease in charge-transfer resistance, evidencing the effective interfacial carrier separation in the ZnFe2O4/Bi2O2CO3 (ZB) composites. Photocatalytic evaluation showed that the composites performed better than either ZnFe2O4 or Bi2O2CO3 alone, with ZB (1:7) achieving the best activity by degrading similar to 61% of BPA within 4 h of simulated sunlight, corresponding to similar to 2.3 and similar to 2.1 times higher efficiency compared to ZnFe2O4 and Bi2O2CO3, respectively. BPA degradation obeyed pseudo-first-order kinetics (R-2 = 0.9858), yielding a rate constant of 83 x 10(-3) min(-1). Quenching tests confirmed photoinduced holes as the main reactive species, consistent with a direct Z-scheme that preserves redox potential and limits recombination. The ZnFe2O4/Bi2O2CO3 heterojunction showed good stability with moderate recycling losses, while extended light absorption and improved charge separation significantly boosted BPA degradation efficiency.

Microalgal treatment of palm oil mill effluent (POME) offers a route for simultaneous wastewater remediation and carbon mitigation. However, the relationship between pollutant removal and net carbon exchange under mixotrophic conditions remains unclear. Thus, Chlorella vulgaris was cultivated in diluted POME (5%, 10%, and 15%) for 21 days to evaluate nutrient removal, COD degradation, biomass production, and CO₂ fluxes as a function of organic loading. Carbon partitioning was evaluated using daily CO₂ exchange estimations together with stoichiometric carbon-equivalent calculations derived from COD removal and biomass production, providing a first-order assessment of carbon fluxes. All treatments exhibited rapid initial assimilation followed by stabilization, achieving final removals of up to ~99% ammoniacal nitrogen, 53–69% nitrite, 57–64% nitrate, and 84–87% phosphorus while COD decreased sharply within the first three days (77–82%) and converged to ~83–85% overall removal. Biomass accumulation was highest at 10% POME (1.11 g/L) whereas 15% POME showed transient growth inhibition. Despite comparable COD removal and enhanced biomass at higher loadings, CO₂ concentration measurements combined with stoichiometric carbon-equivalent calculations suggested concentration-dependent differences in carbon exchange trend. Based on this first-order carbon accounting approach, only 5% POME exhibited a negative cumulative CO₂ exchange value (−4.72 g CO₂), indicating net uptake under the assumptions of the concentration-based estimation approach. Meanwhile, 10% and 15% POME remained net emitters (+3.18 g CO₂ and + 20.67 g CO₂), driven by intensified heterotrophic respiration. These findings suggest the existence of an organic-loading threshold beyond which respiratory losses may outweigh photosynthetic carbon fixation, suggesting that COD removal or biomass productivity alone may not adequately represent carbon mitigation and indicating that low-strength POME (~5%) provided the most favorable conditions for carbon-negative performance under the assumptions adopted in this study.

Asian rivers are significant carriers of microplastics, posing major environmental and health risks. It is critical to understand the quantity and characteristics of MPs in freshwater, particularly river water used as a source of drinking water. Microplastic pollution in freshwater is a serious issue, but there is surprisingly little data on it, especially in Malaysia. This study aims to investigate the presence and characteristics of microplastics in Perak River water, specifically at a water treatment plant point of abstraction, to understand the quantity and features of MPs in river water used as a source of drinking water, and to inform mitigation measures to reduce riverine MP contamination. Water samples were collected in February and July 2023 from the point of abstraction near the Perak River in Malaysia. We analyzed microplastics based on size, shape, and polymer type using fluorescence and FTIR microscopy. Fluorescence microscopy detected more particles on average, while FTIR microscopy identified 12 distinct polymer and semi-synthetic polymers, with Rayon and PE dominating. Most MPs’ particle sizes ranged from 1 to 10 µm. MPs in the shape of granules and irregulars were often discovered. Study finds FTIR microscopy a more suitable and accurate method for identifying MPs compared to fluorescence microscopy. Numerous unidentified particles were also detected using FTIR and fluorescence microscopy. This research helps authorities to develop mitigation measures to reduce riverine MP contamination in drinking water.

Carbamazepine (CBZ), as an emerging contaminant, falls under the category known as pharmaceuticals and personal care products (PPCPs). It has adverse effects on both humans and the environment, leading to issues such as defects in the central nervous and digestive systems of humans. Traditional treatment methods have limited effectiveness in degrading CBZ due to its chemical properties, leading to its increased accumulation of CBZ in water bodies, especially during the recent pandemic (COVID-19). The focus of this research is on utilizing g-C3N4/Bi2O2CO3 with different weight percentages, namely 30

Wastewater treatment is crucial to ensure environmental sustainability and the availability of clean water for human consumption. It is of utmost importance that the valuable nutrients in the wastewater are recovered. Recently, many researchers have made interesting discoveries using green waste or minerals to treat wastewater and recover nutrients from wastewater. Nutrients which encourage eutrophication of water resources, such as nitrate, nitrite, ammonium, and phosphorus, are the common ones being explored. The nutrients are adsorbed on sorbents, which are recycled from waste and biodegradable material. Upon adsorption of nutrients, the spent sorbents are categorized as green and eco-friendly material which can be further utilized as a soil conditioner. Thus, this review discussed different types of sorbents and its respective efficacy towards nutrient adsorption and feasibility to be recycled as soil conditioner. Factors affecting the performance of the sorbents were detailed and comparisons were made for the best application as soil conditioner. Suggestion was outlined for future focus areas in this work and potential future application in real case scenarios. This review would be beneficial to researchers to achieve a cradle-to-cradle concept for wastewater nutrient recovery. SUMMARY: Recovery of phosphorus and nitrogen from wastewater using sustainable adsorbents Adsorption efficiency of adsorbents aligning with cradle-to-cradle concept Insights into the advantages and limitations of reported adsorbents Spent adsorbents as soil conditioners, enhancing soil fertility, structure, and promoting sustainable nutrient recycling.

Researchers developed dual-function materials (DFMs) that combine CO2-capturing and methanation catalyst components to reduce carbon dioxide emissions and generate valuable methane in integrated sequential carbon capture and methanation. However, severe oxidation-induced deactivation (high reduction temperature requirements) limits the use of Ni-"Na2O"/Al2O3 DFM in O2-containing applications. Therefore, Ni-"Na2O"/CeO2 DFM is synthesized, as CeO2 lowers the reduction temperature. Nevertheless, it fails to produce CH4 due to the inability to desorb CO2 at methanation temperatures. A two-bed system, with Ni/CeO2 catalyst and "Na2O"/ Al2O3 sorbent in a catalyst-to-sorbent ratio of 2:8, captures an average of 0.1187 mmol CO2/gsorbent-catalyst and produces an average of 0.0727 mmol CH4/gsorbent-catalyst over ten cycles at 300 degrees C. This system shows that a separate catalyst-sorbent system is more suitable than a DFM for O2-containing applications. However, validation of the materials and reactor design requires the presence of high levels of steam in the CO2 capture feed gas for real-world applicability.

Landfilling disposal method has raised many environmental concerns especially water pollution from the discharge of landfill leachate. This study is aimed at investigating degradation of ammonia and removal of color of landfill leachate by electro-persulfate activation using rutheniumiridium coated titanium (Ti-RuO2/IrO2) electrode. Process variables such as reaction time, current density and persulfate dosage were optimized using central composite design via response surface methodology (RSM). RSM models show high coefficient of determination, R2 of 0.9182 and 0.9249 for ammonia-nitrogen (NH3-N) and color respectively. The maximum removal efficiency for NH3-N and color were recorded as 83.7% and 65.8% respectively. Persulfate can be used in oxidation processes as an activating agent to remove NH3-N and color from landfill leachate.

Adsorbents derived from eggshell (ES) have been proven to be effective for a variety of pollutants including organic and inorganic pollutants from different types of wastewater. Calcined eggshell (CES) had demonstrated a significant performance in which are on par with or even exceeds the commercially available adsorbents for phosphorus removal or recovery. This study aims to develop the process flow diagram for large scale production of CES with an overall economic analysis. A process flow diagram was developed starting from the transportation to storage of final product, CES. Calculation of process parameters were based on 1,000kg ES/day with 50% yield after the calcination process, generating about 475 kg CES/day. The total production cost was RM542,809.82 for producing 148, 675 kg of CES per annum. Based on these values, the cost of CES production per kg was estimated as RM3.58 or 0.76 USD. There is a great potential for CES in the future for the remediation of water and air pollutants.

Oil palm fiber (OPF) derived biochar was feasible to be used as an adsorbent in removing pollutants from wastewater, especially ammonia. OPF had shown a significant performance in the removal of ammonia from aquaculture wastewater which is comparable to other studies and commercially available biochars. This study focuses on developing a process flow diagram for an up-scale production of OPF biochar and the economic analysis of the production plant. The process flow diagram includes the transportation, shredding, carbonization, sieving, cooling, and final storage of OPF biochar. Estimated costs were calculated based on 5,000 kg of OPF as the starting material. It is estimated based on the lab scale study that approximately 33% of OPF biochar will be produced on daily basis. The system is expected to produce about 1,567.50 kg/day of OPF biochar. The total production cost was found to be RM1,002,923.18 which includes RM535,217.34 of total operating cost per annum and RM467,705.84 of total capital investments respectively. The production cost for OPF biochar/kg was found to be only RM1.99/kg or $0.44/kg. The price is comparable with other commercially available biochars.

The growth of aquaculture farming has produced more nutrient-rich wastewater. This wastewater contributes to eutrophication in the water bodies. Meanwhile, the bamboo furniture industry generates large amounts of solid waste biomass wastes. Bamboo biomass waste could be used in many valuable ways because it is abundant, and has high strength and cellulose content, but it is still mostly underused and often ends up in landfills. To reduce water pollution and nutrient buildup caused by aquaculture wastewater (AW), capturing nutrients with bamboo-derived biomass offers a sustainable circular solution that turns waste into a valuable resource. This study explores the efficiency of zinc chloride (ZnCl2) activated bamboo biochar (ABB) to recover nitrate from AW. ABB was prepared using different impregnated ratios of ZnCl2 at 500 °C. The best prepared condition was further optimized for adsorption process by varying the dosage of ABB and contact time. Results shows that the most efficient nitrate adsorption was 68.8 % when ZnCl2 ABB was prepared at 500 °C using an impregnation ratio of 3. At optimum process parameter (2.5 g, 150 rpm and 90 min) the adsorption efficiency and capacity were further enhanced to 82.8% and 0.676 mg/g respectively. The adsorption process was well represented by Freundlich and pseudo second-order model. The adsorption efficiency decreased to 63.2 % when tested with actual AW due to other competing contaminants in the actual wastewater. This study demonstrates the potential of ABB as a sustainable nitrate recovery material from AW. Spent ABB could be further exploited as soil conditioner. This study contributes to circular economy practices by promoting nutrient recovery from wastewater and the reutilization of waste biomasses.

Phosphorus is a type of pollutant in aquaculture wastewater that contribute to eutrophication. These pollutants can be removed easily using many different techniques. However, recent focus has shifted from removing these pollutants to recovering them as nutrients to promote sustainability outcomes. Our previous study demonstrated that calcined eggshell is an effective adsorbent for phosphorus from actual aquaculture wastewater. Nevertheless, the potential of reusing the spent phosphorus-recovered calcined eggshell sorbent remain unexplored. Studies has shown that recovered adsorbents can be used as soil conditioners. Thus, this study evaluates the potential of phosphorus-recovered calcined eggshell as a soil conditioner to improve Okra plant growth. Spent adsorbents from previous study was mixed with unconditioned soil at different weight percentages. Raw unconditioned soil is fixed as control and commercial conditioned soil was also used to compare the results. The impact of spent biosorbents on the growth of plants was investigated using Okra seeds. It was found that SCES 1% and SCES 5 % outperformed control samples in terms of plant height, total length and true leaf area. The best fresh weight was obtained for SCES 1% compared to other ratios and control. Nevertheless, commercial conditions soil outperformed all samples as it is fully fertilized artificially. This result demonstrates that nutrient-recovered biosorbents have strong potential for use as soil conditioners. In conclusion, nutrient-recovered biosorbents i.e. phosphorus-recovered calcined eggshell offer a promising, sustainable solution for enhancing soil quality and supporting plant growth.

The existence of ammoniacal nitrogen (NH3-N) in water bodies has received much attention due to its toxicity and impact toward human health and the environment. The nitrogen element in NH3-N can be considered as nutrient and should be recovered for its circular economy. In this study, the feasibility of partial oxidation of oil palm fiber (OPF) on the removal of low concentration NH3-N from aquaculture wastewater was investigated. The OPF biochar preparation process was optimized via response surface methodology using design of experiments. Upon optimization, process study, thermodynamics, kinetics, and mechanism of the removal process was deduced using various parameters and models. The OPF biochar prepared at 300 degrees C, 150 min, and 100 ml air/ min shows highest removal efficiency of NH3-N (71.6 %) in synthetic wastewater. The optimized OPF biochar was tested on actual aquaculture wastewater and the removal was almost similar (72.6 %), however the adsorption capacity was lower compared to the synthetic wastewater. The isotherm data of NH3-N agreed well with linear and non-liner Freundlich model and pseudo second order model for the kinetics. OPF biochar exhibits selective removal of NH3-N in actual aquaculture wastewater. In the removal process oxygen surface functional groups played an important role. It can be concluded that the partially oxidized OPF biochar has a good potential to recover nitrogen from low concentration NH3-N from aquaculture wastewater.

This systematic review aims to comprehensively review and critically analyze the status of microplastics (MPs) in ASEAN countries. 273 publications related to ASEAN were shortlisted for analysis. The findings showed that 28 (10.2%) articles are review-based studies, and 245 articles (89.8%) are data analysis or experiment-based studies published between 2017 and December 31, 2022. Among the 10 ASEAN countries, Indonesia and Malaysia reported the highest number of studies in the year 2021, while Laos has not published any articles on MPs and Myanmar has the least (only one). Most of the samplings of MPs were done in sediments, water sources, and marine ecosystems, followed by studies of solid waste and air. Only 13 articles out of 273 reported on the effects of MPs on human health in Malaysia, Indonesia, Thailand, and Singapore. Microscopy examination and FTIR techniques were commonly used for MP detection. Fiber and fragment shapes and all common colors were identified. Sizes and concentrations of particles were reported randomly without any specific unit of measurement. Removal studies were focused on drinking water. Heterogeneity in sampling methods, analysis techniques, and reporting units hinders comparison and conclusion on the present state of knowledge. Future remedies focus on homogeneity in MPs analysis and characterization. This comprehensive review would be beneficial to policymakers and researchers in ASEAN to develop effective strategies for addressing MPs issues in the future.