To develop a market for biochar, it is imperative that solutions are found to producing biochars that are both high performance and economically viable. While biochar performance can be enhanced via chemical modification, it is likely that optimization of pyrolysis time and temperature is a more cost-effective approach to enhancing performance. This was explored via the transformation of urban garden waste into biochar using a range of preparation conditions (heating temperature, residence time, and heating rate). Biochar yield and Cd²⁺ adsorption performance were optimized using response surface methodology. The “best compromise” yield and Cd²⁺ adsorption performance (49.9% and 40.0 mg/g, respectively) of garden waste biochar were achieved using preparation conditions of 398 ℃, 10 ℃/min, and 30 min. In addition, the quantification of adsorption mechanisms suggested mineral precipitation, ion exchange, functional group complexation, and physical adsorption, accounted for 47.9%, 41.5%, 10.3%, and 0.3% of total adsorbed Cd²⁺ in biochar, respectively. Overall, transformation of garden waste into adsorbents might offer a new market for the utilization of urban garden waste, especially given the size of this waste stream and the challenges it presents to municipal administrations.

Graphical abstract

中文翻译：

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园林废弃物生物炭的优化制备及水溶液中Cd2+吸附机理的定量分析

为了开发生物炭市场，必须找到生产高性能和经济上可行的生物炭的解决方案。虽然生物炭性能可以通过化学改性来提高，但优化热解时间和温度可能是提高性能的更具成本效益的方法。这是通过使用一系列制备条件（加热温度、停留时间和加热速率）将城市花园废物转化为生物炭来探索的。使用响应面法优化生物炭产率和 Cd ²⁺吸附性能。“最佳折衷”收率和 Cd ²⁺在 398 ℃、10 ℃/min 和 30 min 的制备条件下，实现了园林垃圾生物炭的吸附性能（分别为 49.9% 和 40.0 mg/g）。此外，吸附机理的量化表明矿物沉淀、离子交换、官能团络合和物理吸附分别占生物炭总吸附Cd ^{2+的47.9%、41.5%、10.3%和0.3%。}总体而言，将花园垃圾转化为吸附剂可能会为城市花园垃圾的利用提供新的市场，特别是考虑到这种垃圾流的规模及其对市政管理部门的挑战。

图形概要