Dechapanya Wipawee, Khamwichit Attaso
School of Engineering and Technology, Walailak University, 222 Thaiburi, Thasala, Nakhon Si Thammarat, 80160 Thailand.
Biomass and Oil Palm Center of Excellence, Walailak University, 222 Thaiburi, Thasala, Nakhon Si Thammarat, 80160 Thailand.
Heliyon. 2023 Jul 7;9(7):e17250. doi: 10.1016/j.heliyon.2023.e17250. eCollection 2023 Jul.
The conversion of palm kernel shells (PKS), a major agricultural waste from the palm oil sector, into a potentially high-value biosorbent for heavy metals-contaminated wastewater treatments was explored in this work. Following carbonization, the activated PKS was chemically activated by soaking the biochar in a phosphoric acid (HPO) solution at 25 °C. The low-temperature approach benefits from less dangerous acid fume production and operational challenges when compared to the high-temperature procedure. The properties of the biochar were characterized by BET, FTIR, and SEM. The effects of HPO dosage, initial Pb(II) concentration, and adsorbent dosage on removing Pb(II) from synthetic wastewater were investigated in the adsorption study. The activation of PKS biochar with high H3PO4 concentrations led to enhanced removal efficiency. The pseudo-second-order (PSO) kinetic model fitted the experimental data well ( 0.99), indicating that chemisorption was likely involved in the adsorption of Pb(II) onto activated PKS. Pb(II) sorption was possibly promoted by the presence of phosphate moieties on the adsorbent surface. The Langmuir isotherm best described the sorption of Pb(II) onto the activated PKS ( 0.97), giving the calculated maximum adsorption capacity (q) of 171.1 μg/g. In addition to physical sorption, possible adsorption mechanisms included functional group complexation and surface precipitation. Overall, activating PKS biochar with HPO at room temperature could be a promising technique to improve the adsorbent's adsorption efficiency for Pb(II) removal from wastewater.
本研究探索了将棕榈油行业主要农业废弃物棕榈仁壳（PKS）转化为用于处理重金属污染废水的潜在高价值生物吸附剂。碳化后，将生物炭在25℃下浸泡于磷酸（HPO）溶液中对活化的PKS进行化学活化。与高温工艺相比，低温方法产生的酸雾危险性较小且操作难度较低。通过BET、FTIR和SEM对生物炭的性质进行了表征。在吸附研究中，考察了HPO用量、初始Pb（II）浓度和吸附剂用量对从合成废水中去除Pb（II）的影响。高浓度H3PO4对PKS生物炭的活化导致去除效率提高。伪二级（PSO）动力学模型与实验数据拟合良好（ 0.99），表明化学吸附可能参与了Pb（II）在活化PKS上的吸附。吸附剂表面磷酸盐基团的存在可能促进了Pb（II）的吸附。Langmuir等温线最能描述Pb（II）在活化PKS上的吸附（ 0.97），计算得出的最大吸附容量（q）为171.1μg/g。除了物理吸附外，可能的吸附机制还包括官能团络合和表面沉淀。总体而言，室温下用HPO活化PKS生物炭可能是提高吸附剂从废水中去除Pb（II）吸附效率的一种有前景的技术。
