This study was conducted to explore the effectiveness of tea waste (TW) biochar (BC) as an adsorbent for the oxidizable organic contaminants measured as chemical oxygen demand (COD) in produced water (PW). BCs were prepared by modifying the TW with single (pre-pyrolysis) and combined (pre and post pyrolysis) treatments using phosphoric acid and hydrogen peroxide solutions. Based on FTIR, XPS, XRD and BET characterizations, the combined modified BC had higher oxygen-containing functional groups (-OH and -COOH), surface area (82 ± 0.50 m²/g) and pore volume (0.08 ± 0.001 cm ³/g) compared to single modified BC (60 ± 0.50 m²/g, 0.02 ± 0.002 cm ³/g). The Langmuir monolayer adsorption model best fitted both BCs with separation factor $R_{\mathrm{L}}$ < 1, showing favorable adsorption process. The controlling mechanism of the adsorption process was best described by the pseudo-second-order kinetic model with a coefficient of determination value of 0.995. The particle diffusion mechanism was demonstrated by the Weber–Morris plot. Taguchi method was used in Minitab 19 for optimization of operating factors i.e., pH, contact time and BC dosage. Maximum COD removal efficiencies were found to be 89.35 ± 0.5% and 95.5 ± 0.5% for single and combined modified BCs, respectively. The study provides a successful approach towards high level of COD removal from PW while reducing the waste generation and protecting the environment.

进行这项研究的目的是探讨茶渣（TW）生物炭（BC）作为可氧化有机污染物的吸附剂的有效性，该污染物以采出水（PW）中的化学需氧量（COD）进行测量。通过使用磷酸和过氧化氢溶液对TW进行单次（热解前）和联合（热解前和后热解）处理来改性BC。根据FTIR，XPS，XRD和BET表征，改性的BC组合物具有较高的含氧官能团（-OH和-COOH），表面积（82±0.50 m ² / g）和孔体积（0.08±0.001 cm ^3） / g），与单一改性BC（60±0.50 m ² / g，0.02±0.002 cm ³ / g）相比。Langmuir单层吸附模型最适合两个BC且具有分离因子${\mathrm{[R}}_{\mathrm{大号}}$<1，显示有利的吸附过程。吸附过程的控制机理最好用拟二阶动力学模型描述，确定系数为0.995。韦伯-莫里斯图证明了粒子的扩散机制。在Minitab 19中使用Taguchi方法优化操作因素，例如pH，接触时间和BC剂量。发现单个和组合改性BC的最大COD去除效率分别为89.35±0.5％和95.5±0.5％。这项研究提供了一种成功的方法，可以从废物中大量去除COD，同时减少废物产生并保护环境。