Synthesis of highly fluorescent carbon quantum dots from rubber seed shells for the adsorption and photocatalytic degradation of dyes.

The potentials of biomass-based carbon quantum dot (CQD) as an adsorbent for batch adsorption of dyes and its photocatalytic degradation capacity for dyes which are congo red (CR) and methylene blue (MB) have been conducted in this study. The CQDs properties, performance, behaviour, and photoluminescence characteristics were assessed using batch adsorption experiments which were carried out under operating conditions including, temperature, pH and dosage. The morphological analysis revealed that CQDs are highly porous, uniform, closely aligned and multi-layered. The presence of hydroxyl, carboxyl and carbonyl functional groups indicated the significance of the oxygenated functional groups. Spectral analysis of photoluminescence for CQDs confirmed their photoluminescent quality by exhibiting high excitation intensity and possessing greenish-blue fluorescence under UV radiation. The removal percentage of the dyes adsorbed for both CR and MB dyes was 77% and 75%. Langmuir isotherm and pseudo-second-order models closely fitted the adsorption results. Thermodynamics analysis indicated that the adsorption process was exothermic and spontaneous, with excellent reusability and stability. The degradation efficiency of CQDs on both dyes was more than 90% under sunlight irradiation and obeyed the first-order kinetic model. These results demonstrated CQDs to be an excellent adsorbent and outstanding photocatalyst for organic dye degradation.

Environmental performance of a photovoltaic brackish water reverse osmosis for a cleaner desalination process: A case study.

Reverse osmosis (RO) membrane-based desalination system with various configurations has emerged as a critical option for reclaiming brackish water. This study aims to evaluate the environmental performance of the combination of photovoltaic-reverse osmosis (PVRO) membrane treatment system via life cycle assessment (LCA). The LCA was calculated using SimaPro v9 software with ReCiPe 2016 methodology and EcoInvent 3.8 database following the ISO 14040/44 series. The findings identified the chemical and electricity consumption at both the midpoint and endpoint level across all impact categories with terrestrial ecotoxicity (27.59 kg 1,4-DCB), human non-carcinogenic toxicity potential (8.06 kg 1,4-DCB) and GWP (4.33 kg CO2 eq) as the highest impacts for the PVRO treatment. As for the endpoint level, the desalination system affected human health, ecosystems and resources at 1.39 × 10-5 DALY, 1.49 × 10-7 species·year and 0.25 USD2013 respectively. The construction phase for the overall PVRO treatment plant was also assessed and impacted less significantly compared to the operational phase. Three different scenarios (i.e. S1: Grid input (Baseline); S2: Photovoltaic (PV)/Battery; S3: PV/Grid) based on different sources of electricity used were also compared as electricity consumption is one of the significant impacts in the operational phase. The study found that S2 had the lowest environmental impact, while S1 contributed the highest when both midpoint and endpoint approaches are considered.

Exploring the factors influencing consumer behaviours and practices towards sustainable WEEE management in Putrajaya, Malaysia.

The disposal practises and preferences of household waste from electrical and electronic equipment disposal (WEEE) are essential components in material flow analysis (MFA). Nevertheless, the synergistic of consumers' behaviours and preferences with the disposal of different WEEE has yet to be investigated in depth. This study examined several consumer features of WEEE management using a quantitative questionnaire survey, including consumers' disposal behaviours and preferences. As a Malaysian federal government administrative centre, and model of a contemporary and sustainable Malaysian city, Putrajaya was chosen as the study area. Using stratified random sampling, the questionnaire was distributed through face-to-face and online surveys among households across 20 precincts within Putrajaya. From June 2021 to January 2022, 500 surveys were distributed over seven months, and IBM SPSS Statistic version 26 was used to analyse the data. The result shows that 80% of respondents have a good knowledge of WEEE management and are fully aware of the dangerous materials they have in their WEEE. 75% said they would recycle their WEEE, but only 44% said they would separate it from other household wastes. It was also shown that 88% of the household were willing to pay a collection fee of at least RM 10 for each collection. This analysis found that Extended Producer Responsibility (EPR) mechanisms can assist in overcoming weaknesses in WEEE management by including beneficial schemes to incentivise consumers to improve current waste policies. In the meantime, governments, media, and local non-governmental organisations may help by increasing awareness of effective and sustainable WEEE management.

Life cycle assessment of bioelectrochemical and integrated microbial fuel cell systems for sustainable wastewater treatment and resource recovery.

Bioelectrochemical system (BES) is an emerging technology that can treat wastewater via microbial activity while producing energy simultaneously. The system can couple with conventional systems to improve system performance. This study aims to compare the environmental performance of BES and the integrated microbial fuel cell (MFC) systems via a life cycle assessment methodology and identify the major environmental hotspots of the system. Fifteen treatment options are assessed with the ReCiPe 2016 characterization method using SimaPro 9.2 software. The results show double chamber air-cathode microbial electrolysis cell (MEC1) and membrane distillation integrated MFC (MD + MFC) treatment options present as the most environmental favourable among the BES and integrated MFC systems, respectively, due to the offset of the environmental loads from the avoided impacts contributed by their value-added by-product, which is hydrogen fuel for MEC1 and tap water for MD + MFC. Electricity consumption dominates the environmental loads of all the BES options for up to 90% of the global warming impact category. The environmental benefits from the electricity generation of BES are minor (i.e., MFC: 0.01-2% while microbial desalination cell: 0.01-7% of the total environmental impact in a system) to offset the environmental loads incurred by the system. Platinum-based cathode incurs 2.5-24 times higher environmental burdens than non-platinum configurations in MFC under the human carcinogenic toxicity impact category. In line with Sustainable Development Goals 6 and 13, this study provides scientific references to wastewater treatment stakeholders in selecting suitable BES and integrated MFC systems to improve water sanitation and address climate change simultaneously.

Metal-Doped Graphitic Carbon Nitride Nanomaterials for Photocatalytic Environmental Applications-A Review.

In the current world situation, population and industrial growth have become major problems for energy and environmental concerns. Extremely noxious pollutants such as heavy metal ions, dyes, antibiotics, phenols, and pesticides in water are the main causes behind deprived water quality leading to inadequate access to clean water. In this connection, graphite carbon nitride (GCN or g-C3N4) a nonmetallic polymeric material has been utilized extensively as a visible-light-responsive photocatalyst for a variety of environmental applications. This review focuses on recent developments in the design and photocatalytic applications of metal-doped GCN-based nanomaterials in CO2 photoreduction, water splitting toward hydrogen production, bacterial disinfection, and organic pollutant degradation. Additionally, this review discusses various methods of using GCN-based materials to optimize dye sensitization, metal deposition, ion doping, and their environmental applications.

Life Cycle Assessment of an Integrated Membrane Treatment System of Anaerobic-Treated Palm Oil Mill Effluent (POME).

A life cycle assessment of anaerobic-treated palm oil mill effluent (POME) was conducted to assess the environmental performance on two integrated treatment processes: the typical hollow fiber membrane ultrafiltration module coupled with adsorption and electro-oxidation as pretreatment. The analysis was undertaken using the ReCiPe 2016 method and SimaPro v9 software was employed using a 'cradle-to-gate' approach. The results showed that hollow fiber membrane from the adsorption integrated membrane impacted significantly at 42% to 99% across all impact categories for both processes. Overall, the electro-oxidation integrated membrane was discovered to have a lesser environmental impact, particularly on the ozone formation (human health) (HOFP) at 0.38 kg NOx-eq in comparison to the adsorption integrated membrane at 0.66 kg NOx-eq. The total characterization factor of the endpoint category for human health is 8.61 × 10-4 DALY (adsorption integrated membrane) and 8.45 × 10-4 DALY (electro-oxidation integrated membrane). As membrane treatment is closely linked to energy consumption, the environmental impact with different sources of energy was evaluated for both processes with the impacts decreasing in the following order: Grid > Biogas > Grid/Solar. Future research should concentrate on determining the overall 'cradle-to-grave' environmental impact of treating POME, as well as other scenarios involving membrane treatment energy utilization using LCA. This study can help decision-makers in identifying an environmentally sustainable POME treatment and management, especially in Malaysia.

A Content Review of Life Cycle Assessment of Nanomaterials: Current Practices, Challenges, and Future Prospects.

This paper provides a comprehensive review of 71 previous studies on the life cycle assessment (LCA) of nanomaterials (NMs) from 2001 to 2020 (19 years). Although various studies have been carried out to assess the efficiency and potential of wastes for nanotechnology, little attention has been paid to conducting a comprehensive analysis related to the environmental performance and hotspot of NMs, based on LCA methodology. Therefore, this paper highlights and discusses LCA methodology's basis (goal and scope definition, system boundary, life cycle inventory, life cycle impact assessment, and interpretation) to insights into current practices, limitations, progress, and challenges of LCA application NMs. We found that there is still a lack of comprehensive LCA study on the environmental impacts of NMs until end-of-life stages, thereby potentially supporting misleading conclusions, in most of the previous studies reviewed. For a comprehensive evaluation of LCA of NMs, we recommend that future studies should: (1) report more detailed and transparent LCI data within NMs LCA studies; (2) consider the environmental impacts and potential risks of NMs within their whole life cycle; (3) adopt a transparent and prudent characterization model; and (4) include toxicity, uncertainty, and sensitivity assessments to analyze the exposure pathways of NMs further. Future recommendations towards improvement and harmonization of methodological for future research directions were discussed and provided. This study's findings redound to future research in the field of LCA NMs specifically, considering that the release of NMs into the environment is yet to be explored due to limited understanding of the mechanisms and pathways involved.

Fabrication of Eco-Friendly Polyelectrolyte Membranes Based on Sulfonate Grafted Sodium Alginate for Drug Delivery, Toxic Metal Ion Removal and Fuel Cell Applications.

Polyelectrolyte membranes (PEMs) are a novel type of material that is in high demand in health, energy and environmental sectors. If environmentally benign materials are created with biodegradable ones, PEMs can evolve into practical technology. In this work, we have fabricated environmentally safe and economic PEMs based on sulfonate grafted sodium alginate (SA) and poly(vinyl alcohol) (PVA). In the first step, 2-acrylamido-2-methyl-1-propanesulphonic acid (AMPS) and sodium 4-vinylbenzene sulfonate (SVBS) are grafted on to SA by utilizing the simple free radical polymerization technique. Graft copolymers (SA-g-AMPS and SA-g-SVBS) were characterized by 1H NMR, FTIR, XRD and DSC. In the second step, sulfonated SA was successfully blended with PVA to fabricate PEMs for the in vitro controlled release of 5-fluorouracil (anti-cancer drug) at pH 1.2 and 7.4 and to remove copper (II) ions from aqueous media. Moreover, phosphomolybdic acids (PMAs) incorporated with composite PEMs were developed to evaluate fuel cell characteristics, i.e., ion exchange capacity, oxidative stability, proton conductivity and methanol permeability. Fabricated PEMs are characterized by the FTIR, ATR-FTIR, XRD, SEM and EDAX. PMA was incorporated. PEMs demonstrated maximum encapsulation efficiency of 5FU, i.e., 78 ± 2.3%, and released the drug maximum in pH 7.4 buffer. The maximum Cu(II) removal was observed at 188.91 and 181.22 mg.g-1. PMA incorporated with PEMs exhibited significant proton conductivity (59.23 and 45.66 mS/cm) and low methanol permeability (2.19 and 2.04 × 10-6 cm2/s).

Fabrication of Polyelectrolyte Membranes of Pectin Graft-Copolymers with PVA and Their Composites with Phosphomolybdic Acid for Drug Delivery, Toxic Metal Ion Removal, and Fuel Cell Applications.

In this study, a simple method for the fabrication of highly diffusive, adsorptive and conductive eco-friendly polyelectrolyte membranes (PEMs) with sulfonate functionalized pectin and poly(vinyl alcohol)(PVA) was established. The graft-copolymers were synthesized by employing the use of potassium persulfate as a free radical initiator from pectin (PC), a carbohydrate polymer with 2-acrylamido-2-methyl-1-propanesulphonic acid (AMPS) and sodium 4-vinylbenzene sulphonate (SVBS). The PEMs were fabricated from the blends of pectin graft-copolymers (PC-g-AMPS and PC-g-SVBS) and PVA by using a solution casting method, followed by chemical crosslinking with glutaraldehyde. The composite PEMs were fabricated by mixing phosphomolybdic acid with the aforementioned blends. The PEMs were successfully characterized by FTIR, XRD, SEM, and EDAX studies. They were assessed for the controlled release of an anti-cancer drug (5-fluorouracil) and the removal of toxic metal ions (Cu2+) from aqueous media. Furthermore, the composite PEMs were evaluated for fuel cell application. The 5-fluorouracil release capacity of the PEMs was found to be 93% and 99.1% at 300 min in a phosphate buffer solution (pH = 7.4). The highest Cu2+ removal was observed at 206.7 and 190.1 mg/g. The phosphomolybdic acid-embedded PEMs showed superior methanol permeability, i.e., 6.83 × 10-5, and 5.94 × 10-5, compared to the pristine PEMs. Furthermore, the same trend was observed for the proton conductivities, i.e., 13.77 × 10-3, and 18.6 × 10-3 S/cm at 30 °C.

Porphyrin N-Pincer Pd(II)-Complexes in Water: A Base-Free and Nature-Inspired Protocol for the Oxidative Self-Coupling of Potassium Aryltrifluoroborates in Open-Air.

Metalloporphyrins (and porphyrins) are well known as pigments of life in nature, since representatives of this group include chlorophylls (Mg-porphyrins) and heme (Fe-porphyrins). Hence, the construction of chemistry based on these substances can be based on the imitation of biological systems. Inspired by nature, in this article we present the preparation of five different porphyrin, meso-tetraphenylporphyrin (TPP), meso-tetra(p-anisyl)porphyrin (TpAP), tetrasodium meso-tetra(p-sulfonatophenyl)porphyrin (TSTpSPP), meso-tetra(m-hydroxyphenyl)porphyrin (TmHPP), and meso-tetra(m-carboxyphenyl)porphyrin (TmCPP) as well as their N-pincer Pd(II)-complexes such as Pd(II)-meso-tetraphenylporphyrin (PdTPP), Pd(II)-meso-tetra(p-anisyl)porphyrin (PdTpAP), Pd(II)-tetrasodium meso-tetra(p-sulfonatophenyl)porphyrin (PdTSTpSPP), Pd(II)-meso-tetra(m-hydroxyphenyl)porphyrin (PdTmHPP), and Pd(II)-meso-tetra(m-carboxyphenyl)porphyrin (PdTmCPP). These porphyrin N-pincer Pd(II)-complexes were studied and found to be effective in the base-free self-coupling reactions of potassium aryltrifluoroborates (PATFBs) in water at ambient conditions. The catalysts and the products (symmetrical biaryls) were characterized using their spectral data. The high yields of the biaryls, the bio-mimicking conditions, good substrate feasibility, evading the use of base, easy preparation and handling of catalysts, and the application of aqueous media, all make this protocol very attractive from a sustainability and cost-effective standpoint.

Removal of inorganic pollutants using electrocoagulation technology: A review of emerging applications and mechanisms.

Electrocoagulation (ECoag) technique has shown considerable potential as an effective method in separating different types of pollutants (including inorganic pollutants) from various sources of water at a lower cost, and that is environmentally friendly. The EC method's performance depends on several significant parameters, including current density, reactor geometry, pH, operation time, the gap between electrodes, and agitation speed. There are some challenges related to the ECoag technique, for example, energy consumption, and electrode passivation as well as its implementation at a larger scale. This review highlights the recent studies published about ECoag capacity to remove inorganic pollutants (including salts), the emerging reactors, and the effect of reactor geometry designs. In addition, this paper highlights the integration of the ECoag technique with other advanced technologies such as microwave and ultrasonic to achieve higher removal efficiencies. This paper also presents a critical discussion of the major and minor reactions of the electrocoagulation technique with several significant operational parameters, emerging designs of the ECoag cell, operating conditions, and techno-economic analysis. Our review concluded that optimizing the operating parameters significantly enhanced the efficiency of the ECoag technique and reduced overall operating costs. Electrodes geometry has been recommended to minimize the passivation phenomenon, promote the conductivity of the cell, and reduce energy consumption. In this review, several challenges and gaps were identified, and insights for future development were discussed. We recommend that future studies investigate the effect of other emerging parameters like perforated and ball electrodes on the ECoag technique.

Current Trends in the Application of Nanomaterials for the Removal of Pollutants from Industrial Wastewater Treatment-A Review.

In the recent decades, development of new and innovative technology resulted in a very high amount of effluents. Industrial wastewaters originating from various industries contribute as a major source of water pollution. The pollutants in the wastewater include organic and inorganic pollutants, heavy metals, and non-disintegrating materials. This pollutant poses a severe threat to the environment. Therefore, novel and innovative methods and technologies need to adapt for their removal. Recent years saw nanomaterials as a potential candidate for pollutants removal. Nowadays, a range of cost-effective nanomaterials are available with unique properties. In this context, nano-absorbents are excellent materials. Heavy metal contamination is widespread in underground and surface waters. Recently, various studies focused on the removal of heavy metals. The presented review article here focused on removal of contaminants originated from industrial wastewater utilizing nanomaterials.

Synthesis of porous 2D layered nickel oxide-reduced graphene oxide (NiO-rGO) hybrid composite for the efficient electrochemical detection of epinephrine in biological fluid.

In the present research work, 2D-Porous NiO decorated graphene nanocomposite was synthesized by hydrothermal method to monitored the concentration of epinephrine (EPI). The morphology (SEM and TEM) results confirmed 2D-Porous NiO nanoparticles firmly attached over graphene nanosheets. FTIR and XPS analysis confirmed the formation of nickel oxide formation and complete reduction of GO to rGO. The electrochemical activity of the proposed NiO-rGO/GCE modified electrode on epinephrine was analyzed by simple cyclic voltammetry technique. The proposed low cost NiO-rGO/GCE modified electrode showed excellent catalytic activity over GCE and rGO/GCE electrodes. Due to its high conductivity and charge transfer ability of the NiO-rGO/GCE modified electrode exhibited high sensitivity of EPI at optimized conditions. The anodic peak current of the EPI linearly increases with increasing the concertation of EPI. A wide linear range (50 µM-1000 µM) was achieved with high correlation coefficient (R2 = 0.9986) and the limit of detection (LOD) of NiO-rGO/GCE modified electrode was calculated to be 10 µM. NiO-rGO/GCE electrode showed good stability and repeatability towards the EPI oxidation. Mainly, the proposed NiO-rGO/GCE modified electrode showed good sensitivity of EPI in the human biological fluid with high recovery percentage. The low cost, NiO-rGO/GCE electrode could be the promising sensor electrode for the detection of Epinephrine in the real samples.

Investigation on (Zn) doping and anionic surfactant (SDS) effect on SnO2 nanostructures for enhanced photocatalytic RhB dye degradation.

Herein we reported the effect of doping and addition of surfactant on SnO2 nanostructures for enhanced photocatalytic activity. Pristine SnO2, Zn-SnO2 and SDS-(Zn-SnO2) was prepared via simple co-precipitation method and the product was annealed at 600 °C to obtain a clear phase. The structural, optical, vibrational, morphological characteristics of the synthesized SnO2, Zn-SnO2 and SDS-(Zn-SnO2) product were investigated. SnO2, Zn-SnO2 and SDS-(Zn-SnO2) possess crystallite size of 20 nm, 19 nm and 18 nm correspondingly with tetragonal structure and high purity. The metal oxygen vibrations were present in FT-IR spectra. The obtained bandgap energies of SnO2, Zn-SnO2 and SDS-(Zn-SnO2) were 3.58 eV, 3.51 eV and 2.81 eV due to the effect of dopant and surfactant. This narrowing of bandgap helped in the photocatalytic activity. The morphology of the pristine sample showed poor growth of nanostructures with high level of agglomeration which was effectively reduced for other two samples. Product photocatalytic action was tested beneath visible light of 300 W. SDS-(Zn-SnO2) nanostructure efficiency showed 90% degradation of RhB dye which is 2.5 times higher than pristine sample. Narrow bandgap, crystallite size, better growth of nanostructures paved the way for SDS-(Zn-SnO2) to degrade the toxic pollutant. The superior performance and individuality of SDS-(Zn-SnO2) will makes it a potential competitor on reducing toxic pollutants from wastewater in future research.

The removal of anionic and cationic dyes from an aqueous solution using biomass-based activated carbon.

In this study, two biomass-based adsorbents were used as new precursors for optimizing synthesis conditions of a cost-effective powdered activated carbon (PAC). The PAC removed dyes from an aqueous solution using carbonization and activation by KOH, NaOH, and H2SO4. The optimum synthesis, activation temperature, time and impregnation ratio, removal rate, and uptake capacity were determined. The optimum PAC was analyzed and characterized using Fourier-transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), a field emission scanning electron microscope (FESEM), Zeta potential, and Raman spectroscopy. Morphological studies showed single-layered planes with highly porous surfaces, especially PAC activated by NaOH and H2SO4. The results showed that the experimental data were well-fitted with a pseudo-second-order model. Based on Langmuir isotherm, the maximum adsorption capacity for removing methylene blue (MB) was 769.23 mg g-1 and 458.43 mg g-1 for congo red (CR). Based on the isotherm models, more than one mechanism was involved in the adsorption process, monolayer for the anionic dye and multilayer for the cationic dye. Elovich and intraparticle diffusion kinetic models showed that rubber seed shells (RSS) has higher α values with a greater tendency to adsorb dyes compared to rubber seed (RS). A thermodynamic study showed that both dyes' adsorption process was spontaneous and exothermic due to the negative values of the enthalpy (ΔH) and Gibbs free energy (ΔG). The change in removal efficiency of adsorbent for regeneration study was observed in the seventh cycles, with a 3% decline in the CR and 2% decline in MB removal performance. This study showed that the presence of functional groups and active sites on the produced adsorbent (hydroxyl, alkoxy, carboxyl, and π - π) contributed to its considerable affinity for adsorption in dye removal. Therefore, the optimum PAC can serve as efficient and cost-effective adsorbents to remove dyes from industrial wastewater.

Comparison of the effects of two laser photobiomodulation techniques on bio-physical properties of Zea mays L. seeds.

BACKGROUND: Laser applications in agriculture have recently gained much interest due to improved plant characteristics following laser treatment before the sowing of seeds. In this study, maize seeds were exposed to different levels of laser treatment prior to sowing to improve their field performance. The aim of this study is to evaluate the impact of pre-sowing laser photobiomodulation on the field emergence and growth of treated maize seeds. METHODS: The maize seeds were first photobiomodulated with two lasers: 1) a helium-neon (He-Ne) red laser (632.8 nm), and 2) a neodymium-doped yttrium aluminum garnet (Nd:YAG) green laser (532 nm). Following three replications of randomized complete block design (RCBD), four irradiation treatments were applied (45 s, 65 s, 85 s, and 105 s) at two power intensities (2 mW/cm2 and 4 mW/cm2). RESULTS: Based on the results, maize seeds pretreated with a green laser and 2 mW/cm2 power intensity for 105 s exhibited the highest rate of seed emergence (96%) compared to the untreated control seeds with a lower seed emergence rate (62.5%). Furthermore, maize seeds treated with a red laser for 45 s showed an increased vigor index compared to the other treatment options and the control (P < 0.01). The treatment groups also showed statistically significant differences in seedling growth characteristics compared to the control group p < 0.01. The green laser produced a significant enhancement of about 24.20 cm in seedling length, 8.2 leaves/plant, and 3.4 cm in stem diameter compared to the untreated seeds. Moreover, the green laser treatment showed 57.4 days to anthesis, which was earlier than the untreated seeds (61.4 days). The results showed that the protein, oil, and starch contents of the seeds irradiated with the green laser were 17.54%, 6.18%, and 73.32%, respectively, compared to the seeds irradiated by the red laser with 16.51%, 6.33%, and 71.05%, respectively. CONCLUSIONS: The photo biomodulation of maize seeds using a green laser light can improve the field emergence, seedling growth, and seed quality of the treated seed compared to the red laser treatment.

Environmental Performance of Small-Scale Seawater Reverse Osmosis Plant for Rural Area Water Supply.

Seawater desalination is an alternative technology to provide safe drinking water and to solve water issues in an area having low water quality and limited drinking water supply. Currently, reverse osmosis (RO) is commonly used in the desalination technology and experiencing significant growth. The aim of this study was to analyze the environmental impacts of the seawater reverse osmosis (SWRO) plant installed in Kampung Pantai Senok, Kelantan, as this plant was the first installed in Malaysia. The software SimaPro 8.5 together with the ReCiPe 2016 database were used as tools to evaluate the life cycle assessment (LCA) of the SWRO plant. The results showed that the impact of global warming (3.90 kg CO2 eq/year) was the highest, followed by terrestrial ecotoxicity (1.62 kg 1,4-DCB/year) and fossil resource scarcity (1.29 kg oil eq/year). The impact of global warming was caused by the natural gas used to generate the electricity, mainly during the RO process. Reducing the environmental impact can be effectively achieved by decreasing the electricity usage for the seawater desalination process. As a suggestion, electricity generation can be overcome by using a high-flux membrane with other suitable renewable energy for the plant such as solar and wind energy.

Application of life cycle assessment for desalination: Progress, challenges and future directions.

The sustainability performance of the desalination processes has received increasing attention in recent years. In this study, the current progress and future perspective of a life cycle assessment (LCA) of desalination technology in 62 previous studies have been reviewed for the period 2004-2019. It was found that the number of LCA studies related to seawater reverse osmosis has gained popularity compared to other types of desalination technologies. The review emphasized the application of LCA to desalination by means of research objective, scope of study, life stages, and impact assessment. Although previous LCA studies were conducted to assess the environmental performance of the desalination technology, little attention was given to evaluating the impact of other sustainability aspects (i.e., economic and social). The latter part of this study discusses the challenges, feasibility, and recommendations for future LCA studies on desalination technology. The integration of the LCA approach with other approaches allows a comprehensive assessment of the sustainability performance of desalination technology. Thus, the combined approaches should be explored in future studies to gain insight into the sensitivity and uncertainty of the data to make an assessment that can be useful in policy-making.

An LCA-Based Environmental Performance of Rice Production for Developing a Sustainable Agri-Food System in Malaysia.

This study aims to assess the environmental impacts of conventional and organic rice cultivations and proposes a sustainable conceptual framework of rice farming based on the life cycle assessment (LCA) approach. A cradle-to-gate LCA was performed by using the ReCiPe 2016 method and SimaPro 8.5 software. The functional unit was one ton of rice grains harvested. Primary data were obtained from the farmer, while secondary data were collected from Ecoinvent 3.0, the Agri Footprint 3.0 database and the literature. The total characterization factors for global warming potential (GWP), water consumption potential (WCP) and fossil fuel depletion potential (FFP) were 457.89 kg CO2-eq, 98.18 m3 and 84.56 kg oil-eq, respectively, at the midpoint level for conventional rice, while the impacts for organic rice were 140.55 kg CO2-eq, 29.45 m3 and 22.25 kg oil-eq, respectively. At the endpoint level, the total characterization factors for human health damage (HH), ecosystem damage (ED) and resource availability (RA) for conventional rice were 9.63 × 10-4 DALY, 5.54 × 10-6 species.year and 30.98 Dollar, respectively, while for organic rice, the impacts were 2.60 × 10-4 DALY, 2.28 × 10-6 species.year and 8.44 Dollar, respectively. Rice cultivation impacted the environment, particularly in relation to three impact categories: GWP, WCP and FFP. The cultivation phase of rice production was the main contributor to environmental impacts due to the production and application of fertilizer and pesticides. It can be concluded that the application of LCA in agricultural sector is able to provide information and responses for policy makers in understanding the potential environmental impacts at various spatial levels.

CO2 utilization as a soft oxidant for the synthesis of styrene from ethylbenzene over Co3O4 supported on magnesium aluminate spinel: role of spinel activation temperature.

Magnesium aluminate spinel (MgAl2O4) supported Co3O4 catalysts are synthesized and tested for the oxidative dehydrogenation (ODH) of ethylbenzene using CO2 as a soft oxidant. The effect of spinel calcination temperature on the catalytic performance has been systematically investigated. With an increase in the activation temperature from 600 to 900 °C, the active presence of a single-phase MgAl2O4 spinel is observed. A catalyst series consisting of MgAl2O4 spinel with varying Co loadings (10-20 wt%) were prepared and systematically distinguished by ICP, XRD, BET, TPR, NH3-TPD, UV-Vis DRS, FT-IR, XPS, SEM, and TEM. Among the tested cobalt catalysts, 15Co/800MA sample derived by calcination of MgAl2O4 support at 800 °C exhibits the most excellent catalytic performance with the maximum ethylbenzene conversion (≥ 82%). Also, high yields of styrene (≥ 81%) could be consistently achieved on the same active catalyst. Further, the catalyst exhibited almost stable activity during 20 h time-on-stream with a slow decrease in the ethylbenzene conversion from 82 to 59%. However, the selectivity of styrene (98%) stayed almost constant during the reaction. Activation of the MgAl2O4 spinel at 800 °C facilitates a dramatic chemical homogeneity for the alignment of Co3O4 nanoparticles on the surface of the active catalyst. Moreover, the isolated Co3O4 clusters have a strong chemical/electronic interaction with the Mg2+ and Al3+ ions on the support perform a crucial role to achieve the maximum catalytic activity.