Castor leaves-based biochar for adsorption of safranin from textile wastewater

Muhammad Suleman, Muhammad Zafar, Ashfaq Ahmed, Muhammad Usman Rashid, Sadiq Hussain, Abdul Razzaq, Nur Atikah Mohidem, Tahir Fazal, Bilal Haider, Young Kwon Park

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


The prospect of synthesizing biochar from agricultural wastes or by-products to utilize them as a promising adsorbent material is increasingly gaining attention. This research work focuses on synthesizing biochar from castor biomass (CBM) and evaluating its potential as an adsorbent material. Castor biomass-based biochar (CBCs) prepared by the slow pyrolysis process at different temperatures (CBC400C, CBC500C, and CBC600C for 1 h) was investigated for the adsorption of textile dye effluents (safranin). The pyrolysis temperature played a key role in enhancing the morphology, and the crystallinity of the biochar which are beneficial for the uptake of safranin. The CBC600 adsorbent showed a higher safranin dye removal (99.60%) and adsorption capacity (4.98 mg/g) than CBC500 (90.50% and 4.52 mg/g), CBC400 (83.90% and 4.20 mg/g), and castor biomass (CBM) (64.40% and 3.22 mg/g). Adsorption data fitted better to the Langmuir isotherm model than to the Freundlich isotherm model. The kinetics of the adsorption process was described well using the pseudo-second-order kinetic model. The study on the effect of the contact time for the adsorption process indicated that for CBC600, 80% dye removal occurred in the first 15 min of the contact time. After three regeneration cycles, CBC600 exhibited the highest dye removal efficiency (64.10%), highlighting the enhanced reusability of CBCs. The crystalline patterns, functional binding sites, and surface areas of the prepared CBCs (CBC400, CBC500, CBC600) were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and Brunauer–Emmett–Teller surface area measurements, respectively.

Original languageEnglish
Article number6926
JournalSustainability (Switzerland)
Issue number12
StatePublished - 2 Jun 2021


  • Adsorption
  • Biochar
  • Castor biomass
  • Safranin dye
  • Wastewater treatment


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