Research on the Sustainable Improvement Mechanism of the Chemical Engineering and Technology Major Based on the Concepts of Outcome-Based Education–Plan-Do-Check-Act (OBE–PDCA) in Engineering Education

Abstract

This study examines the Chemical Engineering and Technology major at Nanjing Forestry University as a case study to explore a sustainable improvement and development model for the major, grounded in the principles of Outcome-Based Education (OBE) and the Plan-Do-Check-Act (PDCA) framework. In the context of new engineering education and integrating the core concepts of engineering professional education accreditation, this research merges the OBE concept with the PDCA model to promote the sustainable enhancement of the Chemical Engineering and Technology major. The objective is to assess the effectiveness of this professional construction model based on the OBE and PDCA framework in fostering the sustainable development of students. The findings indicate that by establishing a cultivation system aligned with the new economy, restructuring the interdisciplinary curriculum, and implementing a diversified evaluation system, it is feasible to nurture high-quality technical engineering talents equipped with social responsibility, teamwork skills, innovative thinking, and an awareness of sustainable development. This study demonstrates that this professional construction mechanism and model significantly contribute to developing sustainable education, enhancing engineering practice and innovative awareness, and cultivating applied innovative talents among students. Furthermore, this study not only offers new insights for specialty construction but also serves as a practical reference for improving teaching quality and meeting societal demands.

1. Introduction

With the advancement of international exchanges and cooperation, the demand for high-quality engineering technical talent in China is becoming increasingly urgent [1]. The core concepts of engineering education accreditation—student-centered, outcome-oriented, and continuous improvement—have emerged as guiding principles for educational reform [2]. The Outcome-Based Education (OBE) concept, combined with the Plan-Do-Check-Act (PDCA) framework, provides an effective approach to cultivating high-quality interdisciplinary engineering talents [3].

Engineering education accreditation serves as an internationally recognized quality assurance system for engineering education and a standard for the mutual recognition of engineering education and professional qualifications on a global scale [4]. Since the Ministry of Education of China launched the pilot program for engineering education accreditation in 2006, and with China officially becoming a member of the Washington Accord in 2016, this marks a significant progress in the field of higher education’s openness to the outside world [5]. Engineering education accreditation has not only become an inevitable trend in the construction of engineering programs at universities but also serves as an important means and effective pathway to promote the development of new engineering fields [6].

The teaching quality of undergraduate programs directly affects the overall educational quality of universities and the effectiveness of talent development. In this context, the Chemical Engineering and Technology major, as an interdisciplinary discipline, has become increasingly prominent in its status and importance. With the growing societal demand for this major, there is an urgent need for Chemical Engineering and Technology programs to undergo engineering accreditation to assess and address the issues present in the professional development process [7].

Nanjing Forestry University (NFU), a key institution in Jiangsu Province, is distinguished by its interdisciplinary focus on forestry, ecology, and engineering. The Chemical Engineering and Technology major at NFU uniquely emphasizes sustainable biomaterials and green process engineering, aligning with Jiangsu’s strategic priorities in eco-friendly industries. A defining feature of this program is its rigorous emphasis on cultivating students’ engineering practice and innovation capabilities, which are critical for addressing sustainability challenges such as circular economy transitions and pollution control in the Yangtze River Delta [8,9]. By leveraging NFU’s strengths in ecological research and regional industry partnerships, this program serves as an exemplary case for studying mechanisms to develop high-quality technical talents equipped to advance sustainable development goals.

Unlike traditional educational models that rely on static curricula and unidirectional teaching, the integration of OBE and PDCA in this study introduces a dynamic improvement mechanism [10]. This model uniquely addresses challenges in chemical engineering education by embedding sustainability principles, iterative feedback loops, and interdisciplinary collaboration. While OBE and PDCA are established frameworks individually, their synergistic application under China’s engineering accreditation standards offers a novel approach to aligning education with real-time societal and industrial demands.

This study addresses a critical gap in engineering education: the lack of dynamic mechanisms that integrate sustainability principles with industry-aligned skill development. While existing models [2] focus on static outcomes, our OBE–PDCA framework introduces a closed-loop system for continuous curriculum improvement, uniquely embedding sustainability and real-time feedback from stakeholders. This research aims to (1) establish a sustainable improvement mechanism for chemical engineering education, (2) enhance graduates’ employability through interdisciplinary training, and (3) provide empirical evidence for the effectiveness of OBE–PDCA in meeting national industrial strategies.

2. Literature Review

Current engineering education faces several interrelated challenges that hinder the cultivation of industry-ready graduates. These challenges can be categorized into four critical dimensions. First, the lack of clarity in training objectives impedes alignment with evolving industrial demands. As highlighted by Zhang et al. [11], many programs fail to define measurable outcomes, resulting in graduates with mismatched skills. For instance, local universities often adopt uniform training models that neglect regional economic needs, exacerbating skill gaps in emerging sectors [12,13]. This issue is further compounded by insufficient dialogue between academia and industry, as noted in studies on curriculum homogenization [14,15]. Second, insufficient graduation requirements undermine comprehensive competency development. While engineering accreditation standards outline twelve core competencies (e.g., problem-solving and ethics), most curricula lack detailed mappings between courses and these requirements [16], leaving critical skills like critical thinking underdeveloped [17,18]. Third, curriculum structures suffer from rigidity and poor connectivity. Outdated content and slow integration of new technologies, as noted by Neves et al. [19], leave students ill-prepared for modern workplaces. For example, traditional textbooks dominate teaching materials, stifling student engagement and innovation [20,21], while fragmented course sequences fail to address complex engineering problems [22,23]. Finally, the absence of robust evaluation systems limits teaching improvement. Unlike models such as CDIO [2], which emphasize iterative feedback, many institutions lack mechanisms to assess competency attainment holistically [24], hindering sustainable program development [25]. Addressing these gaps requires a paradigm shift toward dynamic, outcome-driven frameworks.

Based on this, this study reveals the issues present in the teaching process of the Chemical Engineering and Technology major by analyzing domestic and international engineering education accreditation standards and the practical training of professional talents in higher education institutions. Domestic refers to Chinese engineering accreditation standards (e.g., China Engineering Education Accreditation Association, CEEAA), while international benchmarks include the Washington Accord and ABET criteria [5].

In contrast to traditional approaches, the OBE–PDCA model proposed here addresses these challenges through three key innovations. First, unlike conventional OBE models that focus on static outcome assessments, our framework introduces dynamic feedback loops via PDCA cycles, enabling real-time curriculum adjustments based on stakeholder input (e.g., employer surveys in Section 3.4). Second, while the CDIO framework [2] prioritizes design-implement cycles, it lacks explicit mechanisms for sustainability integration—a gap bridged by our model through mandatory courses like ‘Green Process Engineering’ and industry partnerships focused on SDGs [4]. Third, compared to accreditation-driven reforms [17], which rely on periodic reviews, our approach embeds continuous improvement into program governance, ensuring alignment with evolving industrial demands.

These innovations collectively address the limitations of existing methods. For instance, fragmented course sequences [19,23] are mitigated by PDCA-driven curriculum mapping, while employer feedback resolves skill mismatches caused by static training models [14]. Recent studies [26,27] validate the efficacy of such integrations, particularly in fostering sustainability competencies and graduate employability.

3. Materials and Methods

This research employs a mixed-methods approach, incorporating qualitative and quantitative methodologies, and was conducted from 2020 to 2023, covering four academic cohorts at Nanjing Forestry University, to analyze the teaching situation and student learning outcomes of the Chemical Engineering and Technology major at Nanjing Forestry University. The study integrates the OBE concept with the PDCA model to establish a dynamic monitoring system for continuous improvement. The curriculum system has been restructured to align with sustainable development goals, emphasizing interdisciplinary collaboration and practical ability cultivation.

Faculty underwent annual training workshops to align with OBE–PDCA principles, covering rubric design for outcome assessments and data-driven feedback analysis. Students actively participated in curriculum restructuring through surveys and focus groups, with their input directly informing PDCA cycles (e.g., adjusting course difficulty in 2022 based on graduate feedback). Implementation followed a structured timeline: curriculum evaluations occurred every semester, while graduate tracking and employer surveys were conducted annually.

3.1. OBE–PDCA Framework Design

This research aims to achieve engineering education objectives and establish a talent cultivation model guided by these twelve standards, fostering students’ fundamental engineering abilities, teamwork and communication skills, personal abilities, and professional ethics, as well as the capabilities of Plan-Do-Check-Act in enterprise or engineering environments [28]. The OBE–PDCA model combines Outcome-Based Education (defining competencies upfront) with Plan-Do-Check-Act cycles (iterative quality improvement). This synergy ensures continuous alignment between course outcomes and evolving industry needs. To ensure the effective implementation of the continuous improvement mechanism for professional courses, this research utilizes the OBE–PDCA comprehensive quality management concept to establish a dynamic monitoring system of monitoring control-evaluation feedback-continuous improvement [29]. Concurrently, the continuous improvement working group will deploy and implement improvement measures based on the feedback received, track the outcomes of these improvements, and create a closed-loop feedback mechanism. As illustrated in Figure 1, the organizational structure of teaching management is presented, clarifying the responsibilities and interrelationships of various organizational levels. This structure ensures comprehensive monitoring and continuous improvement of teaching quality.

3.2. Participant Selection and Data Collection

To cultivate interdisciplinary and innovative talents that align with the development needs of new engineering disciplines, Nanjing Forestry University’s Chemical Engineering and Technology major has defined three core educational objectives: (1) cultivate engineers proficient in sustainable chemical processes, (2) develop innovators capable of addressing regional environmental challenges (e.g., Yangtze River Delta pollution control), and (3) foster professionals with global perspectives on circular economy principles. Guided by these objectives, the program designs training frameworks that synergize with the university’s interdisciplinary strengths in forestry and ecology while supporting Jiangsu Province’s strategic focus on eco-friendly industries [30].

The curriculum redesign prioritizes sustainability competencies, including green chemistry principles, life-cycle analysis, and sustainability ethics, aligning with UN Sustainable Development Goals (SDGs) [4]. For instance, courses such as ‘Green Separation Technology’ embed case studies on regional pollution mitigation, directly linking to Objective 2. Students are trained to analyze and solve complex chemical engineering problems (e.g., wastewater treatment in the Yangtze River Basin) through project-based learning, fostering both technical proficiency and innovative problem-solving skills [31].

In terms of professional development, the program emphasizes ecological awareness and global citizenship. Students engage with international case studies on circular economy models (Objective 3), participate in cross-cultural collaborations, and adhere to engineering ethics that prioritize public health and environmental safety [32,33]. Simultaneously, a strong emphasis on moral cultivation ensures graduates embody patriotic values and social responsibility, contributing to China’s ‘Ecological Civilization’ vision. Finally, lifelong learning modules, such as workshops on emerging green technologies, equip students to adapt to societal and industrial evolution, ensuring sustained professional growth [34].

3.3. Survey Design and Implementation

Based on the aforementioned cultivation goals and requirements, the curriculum for Chemical Engineering and Technology has been systematically restructured with engineering education accreditation as the guiding principle, forming a topology diagram of the curriculum as shown in Figure 2. This diagram illustrates the logical relationships and hierarchical structure between courses while embedding flexibility to address diverse specialty needs, such as organic/inorganic technology, biotechnology, and digital process engineering through modular design. Among them, courses such as ‘Green Separation Technology’ and ‘Chemical Safety and Environmental Protection’ explicitly incorporate the United Nations Sustainable Development Goals (SDGs), dedicating 30% of content to sustainability case studies (e.g., carbon capture in coal-fired plants and waste valorization in textile industries).

3.4. New Format: A Diversified Teaching Quality Evaluation System to Establish a Robust Feedback Mechanism

This study has developed a reasonable evaluation system aimed at comprehensively and objectively assessing teaching quality and its effectiveness. Centered on teaching quality monitoring and course quality evaluation, a complete evaluation mechanism for achieving graduation requirements has been established, covering the entire process from the management of teaching documents and execution of teaching activities to teaching evaluation, thus forming a robust mechanism for evaluating and providing feedback on teaching quality. Figure 3 presents the flow chart of the curriculum system rationality evaluation and teaching quality evaluation and feedback mechanism.

In terms of evaluation methods, taking the assessment of course goal achievement as an example, this study employs a combination of direct and indirect evaluation approaches. Direct evaluation is primarily achieved through the analysis of assessment scores and credit recognition, whereas indirect evaluation relies on student self-assessment. Surveys were distributed annually to graduates and employers via Tencent Docs (Web-based platform, 2023 version), with a response rate of 85%, questions focused on competency alignment with industry needs (e.g., ‘How well did the program prepare you for sustainable engineering practices?’). Participants included all graduates from 2020–2023 (N = 228) and 30 employers from Jiangsu Province’s chemical industry, selected via stratified sampling. Survey questions assessed competency in sustainability, problem-solving, and innovation.

Practical training is embedded via (1) 400+ hours of lab work, (2) virtual reality simulations (VR Simulation Software, Unity 2021.3.16f1 with Oculus SDK v35) for high-risk processes, and (3) industry-sponsored capstone projects (e.g., Sinopec’s refinery optimization). Digital skills are assessed through Python-based (Python 3.9 version) process modeling assignments and IoT-enabled equipment training (Raspberry Pi 4 Model B, Jiangsu Province, China).

(1)

Direct evaluation using assessment score analysis.

According to the teaching syllabus requirements, by calculating the average scores of students on each course goal and combining these with the preset support scores, the achievement value of course goals is further obtained. In general, the data used to evaluate course goals include, but are not limited to, the following: regular scores, examination papers, course design reports, experimental training reports, internship reports, and thesis or design projects. According to the requirements of the course syllabus, the achievement evaluation value Γ_Mi of the i course objective for Course M is calculated using the assessment score analysis method, specifically as follows:

$${\Gamma }_{Mi}=\alpha {\displaystyle \frac{\overline{X}}{X}}+\beta {\displaystyle \frac{\overline{Y}}{Y}}+\dots$$

where $\overline{X}$, $\overline{Y}$, etc., represent the average score of the i-th course objective in each assessment component (such as exam scores, assignment scores, experiment scores, etc.); X, Y, etc., are the supporting scores for the i-th course objective in each assessment component are specified in the course syllabus; α, β, etc., denote the score weight ratios of the different assessment components for the i-th course objective as stipulated in the course syllabus, and (α + β+ …) = 1.

(2)

Indirect evaluation using student self-assessment

Student self-assessment serves as the primary method of indirect evaluation, intended to complement the aforementioned direct evaluation. At the end of the academic year, the program director distributes a questionnaire to gather qualitative feedback from students regarding the effectiveness of course learning and the attainment of course objectives using tools such as Tencent Docs. Student satisfaction is categorized into five levels: very satisfied, satisfied, basically satisfied, dissatisfied, and very dissatisfied, which are assigned scores of 5, 4, 3, 2, and 1, respectively. In particular, if a student is self-assessing as dissatisfied or indicates very low satisfaction, they are required to provide specific reasons for further in-depth analysis and continuous improvement. Based on the data from the survey, the attainment value ψ of the i-th course objective for M course is calculated using a weighted average. The calculation formula is as follows:

$${\mathsf{\Psi }}_{Mi}={\displaystyle \frac{{\sum }_{j=1}^N{F}_{ji}}{N\times 5}}$$

F_ji represents the questionnaire score for the i-th course objective given by the j-th survey respondent, and N is the total number of respondents.

3.5. Strict Design: Continuous Improvement Based on Evaluation Results to Enhance Talent Development Quality

Moreover, engineering education must incorporate a mechanism and practical measures for continuous improvement to ensure the ongoing enhancement of educational and teaching quality [34]. This study has established a professional continuous improvement mechanism based on internal and external evaluations and their feedback, as illustrated in Figure 4. This mechanism clarifies the points of input for improvement (i.e., the basis for improvement) and the points for implementation (i.e., the objects of improvement), adhering to the OBE–PDCA comprehensive quality management philosophy and forming a talent development quality assurance system consisting of the following objective requirements: teaching implementation, evaluation feedback, and improvement enhancement.

Based on the evaluation results of the training objectives, graduation requirements, course objective attainment, and the rationality of the curriculum system, we will conduct a thorough diagnosis of existing issues and implement targeted improvement measures. Specifically, we will revise the training objectives and graduation requirements, carry out continuous improvements across various stages of the professional talent development process, refine the assessment mechanism, and establish a feedback mechanism for teaching outcomes. This aims to ensure that course teaching objectives remain aligned with the established professional training direction, thereby fostering a virtuous interaction between teaching evaluation and teaching improvement, laying a solid foundation for students’ graduation requirements and ensuring the long-term enhancement of talent development quality.

4. Results and Discussion

This section will explore the sustainable improvement mechanism of the Chemical Engineering and Technology major based on the OBE concept and PDCA framework, particularly its influence on discipline competitiveness and graduate employment rates. To effectively assess the sustainable development of the Chemical Engineering and Technology major, we employ a combined approach of both internal and external evaluations, as well as qualitative and quantitative assessments. This dual evaluation mechanism complements each other effectively, forming a comprehensive assessment of the reasonableness of professional training objectives, curriculum system, and graduation requirements [35].

Ultimately, through the statistical analysis of surveys conducted with graduates and employers, a systematic mechanism for sustainable improvement and development pathways for the program is established. Such surveys not only yield firsthand information regarding employers’ recognition of graduates but also provide strong evidence for our analysis of the attainment of professional training objectives, thereby assisting in evaluating whether graduates meet market demands and professional alignment and offering empirical support for revising training goals.

4.1. Key Findings on Curriculum System Rationality

(1)

Evaluation analysis of curriculum system rationality

The latest round of evaluation questionnaires regarding the rationality of the curriculum system was distributed to graduates in June 2022. Graduates strongly endorsed the curriculum’s rationality (76% agreement), particularly its alignment with progressive skill development and practical integration (

Table 1. Survey questionnaire of curriculum system rationality of the graduates.

Curriculum System	Number	Evaluation Index	a	b	c	d	e
1. Curriculum Provision	1	The teaching plan conforms to the law of progressive achievement of ability.	18	4	0	0	0
	2	The courses such as compulsory courses, elective courses, and practical courses are set reasonably.	18	4	0	0	0
	3	Related courses can effectively link up and cooperate closely.	15	6	1	0	0
	4	The course credits and hours are arranged reasonably.	16	6	0	0	0
	5	The theoretical link of the course corresponds to and connects with practice and practice.	19	3	0	0	0
	6	Reflect the characteristics of the school.	15	7	0	0	0
2. Content of Courses	7	Course objectives can correspond to relevant graduation requirement observation points.	19	3	0	0	0
	8	The teaching content can support the course objectives.	17	5	0	0	0
	9	Integrate new technology and new methods into the teaching process.	13	8	1	0	0
	10	Focus on the ability to solve complex chemical engineering and process problems.	17	5	0	0	0
3. Course Assessment	11	Assessment methods and grading standards can support the evaluation of curriculum objectives.	17	5	0	0	0
	12	The assessment content and results can support the evaluation of curriculum objectives.	17	5	0	0	0
4. Graduation Project (Thesis)	13	The topic selection is consistent with the development of the times and the industry.	17	5	0	0	0
	14	Considering humanistic, environmental, ethical, economic, safety and other factors, the ability to comprehensively apply the knowledge is improved.	18	4	0	0	0
5. Innovation Practice Ability	15	The cultivation of innovative practical ability permeates the teaching process.	19	3	0	0	0
	16	The second classroom activity reflects the cultivation of innovation ability.	14	7	1	0	0
Proportion (100%)			76.4%	22.7%	0.9%	0	0

Note: The numbers in the table are the total number of people who selected the item.

).

Through expert validation meetings, faculty discussions, and a questionnaire survey conducted with the 2022 graduating class, the following suggestions were collected: First of all, gradually increase the difficulty of the courses to enhance the role of extracurricular activities; secondly, strengthen the cultivation of students’ innovative abilities to improve their capacity to solve complex engineering problems; finally, better reflect the characteristics of the institution and cultivate chemical engineering and technology professionals who are more aligned with societal needs.

(2)

Evaluation and analysis of course objective achievement

Since the enrollment of students in 2017, we have implemented evaluations of course objective achievement in the Chemical Engineering and Technology major. After each academic year’s course assessments, the teaching staff calculates and analyzes the degree of achievement of the course objectives, producing relevant reports. The evaluation work group summarizes and analyzes the core courses taken by the graduates each June.

Table 2. Course objective achievement degree of chemical engineering and technology major in the past four sessions.

No.	Course Title	The Degree of Achievement in 2020	The Degree of Achievement in 2021	The Degree of Achievement in 2022	The Degree of Achievement in 2023
1	Principles of chemical industry A1	0.79	0.80	0.81	0.80
2	Principles of chemical industry A2	0.82	0.82	0.81	0.83
3	Chemical engineering thermodynamics	0.65	0.75	0.77	0.79
4	Chemical reaction engineering A	0.78	0.82	0.82	0.83
5	Chemical engineering design	0.83	0.88	0.89	0.88
6	Introduction to chemical engineering	0.87	0.88	0.88	0.90
7	Chemical technology	0.72	0.75	0.78	0.76
8	Chemical process research and development	-	0.76	0.77	0.79
9	Chemical container equipment	0.84	0.82	0.83	0.85
10	New separation technology	0.76	0.79	0.77	0.80
11	Technical economy of chemical industry	0.78	0.88	0.86	0.85
12	Chemical safety and environmental protection	0.83	0.79	0.83	0.85
13	Synthesis of fine organic chemicals	0.80	0.82	0.82	0.84
14	Chemical English	0.87	0.89	0.88	0.87
15	Experiment of chemical engineering principles	0.82	0.82	0.84	0.85
16	Graduation thesis	0.83	0.85	0.84	0.85
17	Graduation project	0.83	0.81	0.84	0.85
18	Graduation field work	0.83	0.91	0.88	0.87
19	Course design of chemical design	0.85	0.77	0.84	0.86
20	Course Design for Principles of Chemical Industry	0.82	0.80	0.83	0.84
21	Chemical engineering specialty experiment	0.87	0.90	0.88	0.89

presents statistical data on the course objective achievement of the Chemical Engineering and Technology major over the past four sessions. Through this table, we can track trends in course objective achievement, identify objectives needing further improvement, and assess the effectiveness of improvement measures.

(3)

Analysis of graduation requirement achievement evaluation results

Regarding indirect evaluation, a total of 22 questionnaires were distributed, all of which were returned validly, and the statistical results presented students’ satisfaction ratings and feedback suggestions concerning the various graduation requirements.

Table 3. Comparison of direct and indirect evaluation results of graduation requirement achievement situation of 2022 graduates.

Requirement for Graduation	Direct Evaluation Achievement Evaluation Value	Indirect Evaluation Achievement Evaluation Value	The Results of Assessment
1. Engineering knowledge	0.690	0.755	reach
2. Problem analysis	0.762	0.791	reach
3. Design/develop solutions	0.769	0.755	reach
4. Research	0.792	0.809	reach
5. Use modern tools	0.780	0.791	reach
6. Engineering and society	0.805	0.773	reach
7. Environment and sustainable development	0.829	0.836	reach
8. Professional norm	0.789	0.836	reach
9. Individual and team	0.878	0.882	reach
10. Communication and expression	0.866	0.864	reach
11. Project management	0.856	0.864	reach
12. Lifelong learning	0.861	0.864	reach

compares the direct and indirect evaluation results for the graduation requirements of the 2022 graduates. The analysis results indicate that the graduates of Chemical Engineering and Technology major from 2022 scored achieved for all 12 graduation requirement evaluations. At the same time, the average score for indirect evaluation (0.818) was similar to that of direct evaluation (0.806). This not only reflects high student satisfaction with their learning outcomes but also showcases their diligent and responsible learning attitudes.

The comparison between direct and indirect evaluations is clearly illustrated in Figure 5, providing a basis for a more comprehensive understanding of graduates’ learning achievements. Among these, the evaluation scores of personal and teamwork and communication and expression were relatively high, indicating that graduates received strong training in these areas. However, the evaluation scores of engineering and society and engineering knowledge were comparatively low, suggesting an urgent need to enhance capabilities in these two graduation requirements. Moreover, these results demonstrate that the student training model oriented towards engineering education certification is effective, supporting the sustainable development of the program.

4.2. Trends in Course Objective Achievement

To enhance the graduate tracking feedback mechanism and the social evaluation mechanism involving employers, we regularly conduct surveys to gather feedback and suggestions from graduates and employers regarding the achievement of educational objectives. Recent survey results indicate that, from the perspectives of graduates and employers, the achievement of program objectives is satisfactory, aligns with societal needs, and supports students’ career development within five years post-graduation.

The latest graduate tracking feedback was conducted in July 2023; this program focused on the educational objectives of the 2018 curriculum plan, which incorporates the OBE concept, as the subject of the survey. A total of 30 questionnaires were distributed, with 24 valid responses collected. Social evaluation primarily relies on feedback from employers. We employ various methods, such as questionnaires, discussion forums, and on-site visits, to gain a deeper understanding of graduates’ employment situations and professional development. During this process, we pay attention to employers’ evaluations of graduates’ moral integrity, knowledge base, engineering competencies, and professional qualities, and actively seek their suggestions for talent cultivation. A summary of the specific results from the surveys conducted with graduates and social employers regarding the achievement of educational objectives can be found in

Table 4. Summary of evaluation results of training objective achievement by graduates (alumni) and employers.

Training Objective	Num.	Evaluation Content	Graduate (Alumni) Self-Satisfaction					Employer Satisfaction Evaluation
			a	b	c	d	e	a	b	c	d	e
Moral cultivation	1	Have a correct world outlook, outlook on life and patriotism.	17	7	0	0	0	20	0	0	0	0
	2	Have a good sense of humanities and social sciences and social responsibility, abide by engineering professional ethics, and adhere to the concept of sustainable development in engineering practice.	11	13	0	0	0	10	10	0	0	0
Engineering ability	3	According to industry norms and project requirements, while considering economic, environmental and other factors, chemical process design, reflecting a certain sense of innovation and ability.	9	13	2	0	0	11	9	0	0	0
	4	Ability to analyze and solve complex engineering problems in chemical engineering.	9	13	2	0	0	7	13	0	0	0
	5	Chemical product quality testing and evaluation ability.	10	13	1	0	0	14	5	1	0	0
Professional quality	6	Have an international vision and be able to cross industry and cross culture communication.	7	11	6	0	0	10	8	2	0	0
	7	With good organizational and management ability and team consciousness, able to carry out appropriate project management and effective communication and cooperation between teams.	11	9	4	0	0	13	7	0	0	0
Self-development	8	Take the initiative to improve personal physical and mental health, political consciousness, moral cultivation and so on through various means.	11	11	2	0	0	18	2	0	0	0
	9	Continue to improve their own ability through further study or independent learning to achieve the work ability and professional technical level of the corresponding title.	16	8	0	0	0	17	3	0	0	0

.

It is evident that the self-satisfaction evaluation results of graduates generally align with the satisfaction evaluation results of employers. In the three dimensions of moral cultivation, self-development, and professional quality, both graduates and employers expressed high levels of satisfaction, however, regarding engineering ability, with some graduates and employers rating this aspect as basically satisfied. Through an in-depth analysis of specific evaluation indicators, combined with feedback and suggestions from both graduates and employers concerning the professional training objectives, it was found that graduates’ performance in the areas of engineering knowledge, problem analysis, and design/developing solutions is not satisfactory.

4.3. Graduate Competency Evaluation

Based on the previously mentioned survey data from graduates and employers, along with the feedback received, this study conducted a thorough causal analysis to identify key issues and implement corrective measures. These measures include revising the curriculum, clarifying graduation requirements, adjusting course arrangements, and optimizing the scheduling of teaching activities to enhance students’ core competitiveness and promote better attainment of the training objectives. Through empirical analysis, we validated the effectiveness of the professional development model based on the OBE–PDCA concept in fostering the comprehensive development of students’ knowledge, skills, and abilities.

According to the employment situation of graduates over the past four years (see

Table 5. Graduation rates and degree awarding rates over the last four years based on NFU’s Academic Affairs Office records (2020–2023).

Year	No. of Graduates	Overall Graduation Rate	Overall Degree Attainment Rate	Primary Employment Rate	Final Employment Rate
2020	24	100%	100%	96.2%	100%
2021	22	100%	100%	100%	100%
2022	76	100%	100%	99.6%	100%
2023	106	100%	100%	100%	100%

Note: The statistical time of the first employment rate is August 31 of the year, and the final employment rate is December 31 of the year. The total graduation rate and total degree obtaining rate are the expiration time of the flexible academic system.

) and the categorized employment status (see

Table 6. Classified employment status of students majoring in Chemical Engineering and Technology over the last four years.

Year	Number of Graduates	Engaged in Production, Research and Development, Design, and Other Related Fields of Chemical Industry		Other (Government, Finance, Internet, and Other Industries)		Postgraduate Study (At Home and Abroad)		Waiting for Employment
		Number of People	%	Number of People	%	Number of People	%	Number of People	%
2020	24	14	58.3%	4	16.7%	6	25.0%	0	0
2021	22	11	50.0%	2	9.1%	9	40.9%	0	0
2022	76	44	57.9%	14	18.4%	18	23.7%	0	0
2023	106	63	59.4%	24	22.6%	19	18.0%	0	0

Note: Government institutions include national and local grassroots projects, western plans, selected and transferred students, village officials, conscripts, etc. Graduate self-employment can be classified into the corresponding employment types. The data were collected on August 31 of that year.

), these data provide a visual representation of graduates’ employment conditions and assist in analyzing and assessing the alignment between the achievement of professional training objectives and societal demands. Overall, graduates from this program enjoy a favorable employment situation, achieving a final employment rate of 100%. Among them, an average of 44% of graduates opted to pursue further education, while the majority secured employment in sectors such as materials, chemical engineering, and government institutions. All graduates met the graduation requirements and obtained the corresponding degree certificates. This reflects a strong demand for graduates from this program in society, with the employment rate maintained at over 95% since the program’s inception, stabilizing at 100% in recent years.

4.4. Synthesis of Model Efficacy

The high employment rate in Table 5 is in line with the ideas proposed by Rodríguez-Luna et al. [27], who found that active learning improves employability. However, our model uniquely links employability to sustainability capacity, a gap identified in previous studies [4]. We propose the following improvement measures to continuously enhance the construction and development of the major:

• Carefully design teaching elements to incorporate content such as legal awareness, professional ethics, engineering ethics, and Ecological Civilization, emphasizing cultural awareness. The aim is to cultivate modern engineers with a strong sense of patriotism, social responsibility, and a commitment to excellence.
• Utilize emerging educational platforms such as Rain Classroom and Mooc Classroom to effectively guide students in pre-class preparation and review, encouraging them to engage in immediate post-class exercises. This promotes students’ mastery and understanding of foundational knowledge. Additionally, increase online tutoring, strengthen after-class guidance and problem-solving explanations, and assist students in deepening their understanding of theory through problem-solving.
• Actively encourage students to participate in chemical engineering design competitions, chemical experiment competitions, and other innovative practical activities to further enhance their ability to design and develop solutions through these experiences.

This study makes three pivotal contributions to the field of engineering education. First, it demonstrates the efficacy of integrating OBE and PDCA frameworks to address systemic challenges in chemical engineering education. By establishing a closed-loop system for curriculum development, the model ensures continuous alignment with industry needs, as evidenced by the 100% graduate employment rate (Table 5) and employer recognition of sustainability competencies (Table 4). Second, the research advances sustainable education practices by embedding ecological awareness and green engineering principles into the curriculum, directly supporting China’s ‘Ecological Civilization’ policy. This approach bridges the gap between theoretical training and real-world sustainability challenges, a limitation noted in prior studies [4,23]. Third, the study provides a replicable framework for global engineering accreditation. By restructuring courses to emphasize interdisciplinary collaboration and outcome-based assessments, the model offers institutions a scalable blueprint for cultivating talent aligned with national strategies like ‘Made in China 2025’ [30]. These contributions collectively redefine how engineering programs can harmonize academic rigor, industrial relevance, and sustainability imperatives, further validating the success of the sustainable teaching model within the OBE–PDCA engineering education accreditation framework.

5. Conclusions

The key novelty of this study lies in the integration of OBE’s outcome-driven focus with PDCA’s cyclical improvement process, creating a closed-loop system for sustainable curriculum development. This combination effectively addresses discipline-specific challenges such as outdated content and fragmented skill development, which are rarely tackled in the existing literature (e.g., [3,28]). This research demonstrates that the OBE–PDCA engineering education philosophy not only fosters students’ comprehensive development in knowledge, skills, and competencies (e.g., 100% employment rate, Table 5) but also establishes a systematic sustainable improvement mechanism through quality monitoring and regular curriculum evaluations. Importantly, the program’s emphasis on green engineering and interdisciplinary collaboration directly supports China’s ‘Ecological Civilization’ policy and the ‘Made in China 2025’ initiative, as evidenced by employer recognition of graduates’ sustainability competencies (Table 4) and partnerships with Jiangsu Province’s chemical industries. These findings offer scalable frameworks for engineering education accreditation globally, particularly in aligning curricula with national green industrialization strategies.

The OBE–PDCA framework is designed for adaptability across disciplines. For instance, its modular feedback system can be tailored to mechanical engineering by emphasizing digital manufacturing competencies or to environmental science by integrating climate resilience metrics. Pilot collaborations with Nanjing Forestry University’s Materials Science and Biotechnology departments have shown promising results, with a 15% improvement in graduate industry alignment (2022–2023). Future work will formalize disciplinary adaptation guidelines to ensure seamless implementation in fields with varying knowledge demands, such as biotechnology (e.g., lab-intensive modules) and materials science (e.g., advanced characterization techniques).

However, this study has limitations. First, the single-institution scope may limit generalizability. Second, the four-year data span (2020–2023) necessitates longer-term validation. Third, self-assessment surveys may introduce response bias. To address these, future studies will extend the model to diverse regions (e.g., Guangdong’s manufacturing hubs) and disciplines, incorporating longitudinal tracking of graduates’ career outcomes to assess long-term societal impact. Concurrently, we will deepen the OBE–PDCA philosophy to address emerging challenges in sustainable engineering education, such as integrating AI-driven analytics into feedback loops, ensuring alignment with evolving industrial and ecological demands.