This study investigated the decision-making dynamics for pro-environmental behavior among Thai university students, focusing on reducing the consumption of single-use plastics (SUP). By adopting a dynamic approach to the Theory of Planned Behavior (TPB), the research examined the influence of psychosocial factors, including attitudes, perceived behavioral control, and subjective norms, on SUP reduction intention at different phases of behavior change. Using structural equation modelling, we analyzed quantitative data (n = 317) from the selected universities. The results revealed that attitudes predicted behavioral intentions only among individuals in the contemplation phase of reducing SUP. Attitudes had a small but limited influence on the behavioral intentions of students who had not yet acted. Perceived behavioral control, on the other hand, significantly impacted behavioral intentions across all phases of behavior change, highlighting its importance in SUP reduction. The study also confirmed subjective norms' positive influence on students' behavioral intentions in the pre-contemplation phase. Practical implications suggested segmenting residents based on their behavior change phase so that public policymakers can allocate resources more efficiently and effectively by tailoring campaigns to specific behavior change phases, ultimately promoting sustainable behavior among university students.
Habits , Plastics , Students , Humans , Students/psychology , Universities , Male , Female , Thailand , Young Adult , Intention , Adult , Adolescent , Attitude , Surveys and Questionnaires , Southeast Asian People
The study investigates residents' behavior towards reducing the use of single-use plastic (SUP), specifically in the context of food packaging. The widespread view holds that pro-environmental behavior (PB) results from a person's moral and rational deliberations. In reducing single-use plastic (SUP) consumption and waste, the relative roles of rationality and morality models in validating PB among rural and urban residents are not yet clear. In this empirical study, we compared the relative efficacy of two models for explaining people's SUP reduction behavior: the theory of planned behavior (TPB; rationality) and the value belief norm (VBN; morality). We investigated Thailand's rural (Sichang Island) and metropolitan (Nonthaburi city) areas. As a result, we surveyed people living on Sichang Island (n = 255) and in Nonthaburi city (n = 310). We employed structural equation modeling (SEM) for data analysis in this study. Findings showed that while morality better justified all the study participants' SUP reduction behavior, rationality underpinned behaviors of rural residents, while morality better explained the actions of city residents. We discussed future theoretical development and a policy roadmap based on these findings.
Public Policy , Rural Population , Humans , Thailand , Morals , Surveys and Questionnaires , Plastics
The objective of this research is to find the optimal ratio of glass power (GP) and municipal incinerated bottom ash (MIBA) for producing environmentally friendly interlocking paving blocks. To achieve this, 15 different ratios of mortar samples, sized 5 × 5 × 5 cm, were produced using a 1:3 cement-to-aggregate ratio and a 0.5 water-to-cement ratio. GP was used to substitute cement at 0, 10, and 20% by weight, while MIBA was used to substitute aggregate at 0, 10, 20, 30, and 40% by volume. The samples were divided into two groups and cured with water for 28 and 90 days. Physical testing was performed on the mortar samples after curing. The results show that at 28 days of curing, BA10 and BA20 had compressive strengths of 42.28 and 40.92 MPa respectively, which is higher than the standard for interlocking concrete block (40 MPa) according to TIS 827-2531. At 90 days of curing, GP10BA10, BA10, GP10, GP10BA20, GP20, BA20, and BA30 had compressive strengths of 47.62, 43.63, 43.51, 43.48, 42.73, 42.40, and 40.40 MPa respectively, which also meets the TIS standards.
A study in Nigeria examined the psychological factors affecting face mask disposal behavior (DB) during the COVID-19 pandemic. The Theory of Planned Behavior (TPB) was used, with awareness of consequences and institutional barriers added. 1183 respondents completed an online survey, and structural equation modeling was used to analyze the data. The original TPB model revealed that attitudes, perceived behavioral control, and subjective norms explained 65% of the variance in respondents' behavior. Behavioral intention and perceived behavioral control accounted for 59.3% of the variance in DB. The extended TPB model, which included awareness of consequences and perceived institutional barriers, improved the model's explanatory power by 12.8%. Both TPB models adequately predicted face mask (FM) disposal behavior, with implications for policymakers and waste management authorities to design interventions to promote proper FM disposal behavior.
Managing the large amount and variety of waste produced by university canteens is challenging. This study used life cycle assessment (LCA) to investigate sustainable municipal solid waste (MSW) management solutions for Chulalongkorn University (CU) canteens. This study assessed three scenarios for MSW management in CU canteens: the past scenario (prior to the Chula Zero Waste Project in 2016; S1); the current scenario (2017-2021, when the Chula Zero Waste Project's MSW management system was used; S2); and the future scenario (after 2021 with the new MSW management option for CU canteens under Chula Zero Waste; S3). The obtained results were characterized by eight impact categories: climate change, ozone depletion, terrestrial acidification, freshwater eutrophication, human toxicity, photochemical oxidant formation, particulate matter formation, and fossil depletion. The LCA results show that the future scenario (S3) under the Chula Zero Waste Project is sustainable for MSW management. The most environmentally sustainable MSW plan for CU canteens is to reduce, separate it at the source, and reuse materials instead of landfilling mixed waste.
The objective of this study was to examine the optimal mixing ratio of municipal incinerated bottom ash (MIBA) and PET pellets used as a partial replacement of fine aggregates in the manufacture of cement mortars. As a partial replacement for sand, 15 mortar specimens were prepared by mixing 0%, 10%, 20%, 30%, and 40% municipal incinerated bottom ash (MIBA) (A) and 0%, 10%, and 20% PET pellets (P) in 5 cm × 5 cm × 5 cm cube molds. The cement/aggregate ratio was 1:3, and the water/cement ratio was 0.5 for all specimens. The results showed that the compressive strength of cement mortars decreased when increasing the amount of MIBA and PET pellets. The mortar specimens with 10% PET pellets achieved the highest compressive strength (49.53 MPa), whereas the mortar specimens with 40% MIBA and 20% PET pellets achieved the lowest compressive strength (24.44 MPa). Based on this finding, replacing 10% and 20% sand in cement mortar with only MIBA or only PET pellets could result in compressive strengths ranging from 46.00 MPa to 49.53 MPa.
The purpose of this study was to investigate the best ratio of waste foundry sand (WFS), fly ash (FA), and electric arc furnace slag (EAF slag) for the production of geopolymer bricks. In this research study, WFS, FA, and EAF slag were mixed at the ratio of 70:30:0, 60:30:10, 50:30:20, and 40:30:30 with 8M sodium hydroxide (NaOH) and 98% purity sodium silicate (Na2SiO3) with a ratio of Na2SiO3/8M NaOH = 2.5. The mixtures were compacted in 5 cm × 5 cm x 5 cm molds and cured at an ambient temperature for 28 days. Then, their compressive strength was analyzed. The results showed that the geopolymer bricks with the highest compressive strength were those mixed at the 40:30:30 ratio, with a compressive strength of 25.76 MPa. The strongest bricks were also analyzed using the leaching test to ensure the production involved non-hazardous materials. To compare the environmental impacts of geopolymer bricks and concrete bricks, their effects on climate change, ozone depletion, terrestrial acidification, human toxicity, terrestrial ecotoxicity, and fossil fuel depletion were examined from cradle to grave using SimaPro 8.0.5.13 software. The results of the life cycle assessment (LCA) from cradle to grave showed that the environmental impact of geopolymer brick production was lower in every aspect than that of concrete production. Therefore, geopolymer brick production can reduce environmental impact and can be a value-added use for industrial waste.
This research investigated pyrolysis as a potential method to manage plastic waste in Sichang Island, Thailand. Pyrolysis was chosen to convert waste plastic into fuel oil using Al-Si catalysts derived from cogon grass. The study consisted of three stages. The first stage determined the composition of the waste plastics found in Sichang Island. High-density polyethylene (48%) comprised the highest proportion of the waste plastics, followed by low-density polyethylene (22%), polyethylene terephthalate (13%), polypropylene (10%), and polystyrene (7%). In the second stage, the Al-Si catalysts were prepared from cogon grass (Imperata cylindrica (L.) Beauv) by treating it with acid and calcination. The optimum conditions to extract silica from cogon grass through acid treatment were heating at 700 °C for 2 h, which yielded 97.7% of amorphous silica with a surface area of 172 m2/g and a pore volume of 0.43 cc/g. This amorphous silica was combined with an aluminum precursor to form Al-Si catalysts with 20-80 wt% of Al-Si. The results showed that the surface area of the catalyst increased with increasing aluminum content. The optimum ratio was 60 wt% of Al-Si with a surface area of 200 m2/g. In the final stage, the catalytic properties of the previously prepared Al-Si catalysts in the pyrolysis of waste plastics were evaluated. The catalyst enhanced the plastic cracking process and the oil yield while decreasing the reaction time. The optimum ratio of 60% Al-Si to 10% waste plastic provided the maximum oil yield of 93.11% and the minimum reaction time of 20 min. The results showed that catalytic cracking with 60% Al-Si contributed to a high quantity of oil yield, similar to using a commercial Al-Si catalyst. The results of this research will be applied as an alternative method of recycling plastic for sustainable waste management in Sichang Island.
