Lanthanum hydroxide engineered sewage sludge biochar for efficient phosphate elimination: Mechanism interpretation using physical modelling

Zouhair Elkhlifi, Lotfi Sellaoui, Mengmeng Zhao, Jerosha Ifthikar, Ali Jawad, Irshad Ibran Shahib, Badreddine Sijilmassi, Altaf Hussain Lahori, Rangabhashiyam Selvasembian, Lucas Meili, Eman Abdelnasser Gendy, Zhuqi Chen

Research output: Journal PublicationArticlepeer-review

21 Citations (Scopus)


In the present study, lanthanum hydroxide (La OH)-engineered sewage sludge biochar (La-SSBC) was utilized for efficient phosphate elimination from an aqueous medium. A high adsorption capacity of 312.55 mg P/g was achieved using La-SSBC at 20 °C, which was an excellent adsorbent performance in comparison to other biochar-based adsorbents. Additionally, the performance of La-SSBC was stable even at wider range of pH level, the existence of abundant active anions, and recycling experiments. Statistical physics modeling with the fitting method based on the Levenberg–Marquardt iterating algorithm, as well as various chemical characterizations, suggested the unique double-layered mechanism of phosphate capturing: one functional group of La-SSBC adsorbent describing a prone direction of the PO4 ions on the stabilize surface in a multi-ionic process, forming the first layer adsorption. Additionally, SSBC played an important role by releasing positively charged cations in solution, overcoming the electronic repulsion to form a second layer, and achieving excellent adsorption capacity. The calculation of multiple physicochemical parameters including adsorption energy further evidenced the process. This two-layered mechanism sheds light on the complex interaction between phosphate and biochar. Moreover, the management of sewage sludge associated with the requirement of cost-effectively and environmentally acceptable mode. Therefore, the present investigation demonstrated an efficient approach of the simultaneous sewage sludge utilization and phosphate removal.

Original languageEnglish
Article number149888
JournalScience of the Total Environment
Publication statusPublished - 10 Jan 2022


  • Adsorption
  • Biochar
  • Lanthanum hydorxide
  • Phosphate
  • Sewage sludge
  • Statistical physics modeling

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution


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