This study investigated durian (Durio zibethinus) peels to produce powdered activated carbon (DPAC). The influence of process variables such as carbonization temperature, activation time, contact time, CO2 flow rate, and adsorption dosage was optimized using response surface methodology (RSM). A six-factor and two levels Box–Behnken design (BBD) was used to optimize the parameters. The independent variables were activation temperature (°C), duration (min), CO2 flow rate during the activation process (L/min), irradiation of adsorbent (kGy), irradiation duration (min), and adsorbent dosage (g) while phenol removal (mg/L) was the dependent variable (response). Following the observed correlation coefficient values, the design was fitted to a quadratic model (R2 = 0.9896). The optimal removal efficiency (97.25%) was observed at an activation temperature of 900 °C, activation time of 30 min, CO2 flow rate of 0.05 L/min, irradiation dose of 100 kGy, contact time of 35 min and adsorption dosage of 0.75 g. The optimal DPAC showed a BET surface of 281.33 m2/ g. The removal efficiency was later compared with a commercially available activated carbon which shows a 98.56% phenol removal. The results show that the durian peel could be an effective precursor for making activated carbon for phenol removal, and irradiation can significantly enhance surface activation.

Effect of electron beam irradiation on durian-peel-based activated carbon for phenol removal
    Abstract
    1 Introduction
    2 Methodology
        2.1 Materials
        2.2 Preparation of activated carbon
        2.3 Determination of ash content
        2.4 Determination of moisture content
        2.5 Brunauer–Emmett–Teller surface area analysis
        2.6 Adsorption experiment
        2.7 Analytical methods
        2.8 Experimental design
        2.9 Characterization
    3 Results and discussion
        3.1 Characterization of adsorbent
        3.2 Specific surface area
        3.3 Adsorption modelling of phenol removal using DPAC
        3.4 Optimization of phenol removal using DPAC
        3.5 SEM and EDX
    4 Conclusion
    Anchor 21
    Acknowledgements 
    References

• Major Jane Igbmno(Graphene and Advanced 2D Materials Research Group (GAMRG), School of Science and Technology, Sunway University, No. 5, Jalan Universiti, Bandar Sunway, 47500 Subang Jaya, Selangor, Malaysia)
• Mohammad Khalid(Graphene and Advanced 2D Materials Research Group (GAMRG), School of Science and Technology, Sunway University, No. 5, Jalan Universiti, Bandar Sunway, 47500 Subang Jaya, Selangor, Malaysia, Uttaranchal University, Dehradun, Uttarakhand 248007, India, Division of Research & Development, Lovely Professional University, Phagwara, Punjab 144411, India)
• Gunasunderi Raju(School of Distance Education, Universiti Sains Malaysia, 11800 Pulau Pinang, Malaysia)
• Nabisab Mujawar Mubarak(Petroleum and Chemical Engineering, Faculty of Engineering, Universiti Teknologi Brunei, Bandar Seri Begawan BE1410, Brunei Darussalam)
• Rashmi Walvekar(Department of Chemical Engineering, School of New Energy and Chemical Engineering, Xiamen University Malaysia, Jalan Sunsuria, Bandar Sunsuria, 43900 Sepang, Selangor, Malaysia)
• Chantara Thevy Ratnam(Radiation Processing Technology Division, Malaysian Nuclear Agency (Nuclear Malaysia), Bangi, 43000 Kajang, Selangor, Malaysia)
• Vishal Chaudhary(Research Cell and Department of Physics, Bhagini Nivedita College University of Delhi, New Delhi 110043, India)
• Gokana Mohana Rani(Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Keelung Road, Taipei 10607, Taiwan, Republic of China)