ABSTRACT In areas of water scarcity, recycled municipal wastewaters are being used as water resources for nonpotable applications, especially for irrigation. Such wastewaters often contain elevated levels of dissolved organic carbon (DOC) and solution boron (B). Boron adsorption was investigated on eight arid-zone soils from California and one from Arizona as a function of equilibrium B concentration (0–100 mg L−1) and solution pH (4–10). The B equilibrating solutions were prepared using either recycled wastewaters or synthetic wastewaters containing DOC up to 10 mg L−1. The synthetic wastewaters were synthesized to have the same chemical composition as the recycled wastewaters but contained no DOC. Boron adsorption on the soils increased with increasing solution pH, reaching an adsorption peak near pH 9, and then decreased with further increases in solution pH. The pH-dependent amounts of B adsorption were not statistically significantly different at the 95% level of confidence for both types of waters. For all soils, B adsorption as a function of solution B concentration conformed to the Langmuir adsorption isotherm equation. Boron adsorption maxima, obtained using the Langmuir isotherm, were not statistically significantly different at the 95% confidence level for both types of waters. The constant capacitance surface complexation model was able to predict B adsorption as a function of solution pH using the soil chemical properties: aluminum oxide, inorganic carbon, organic carbon contents, and surface area. The magnitude of B adsorption as a function of solution pH and equilibrium solution B concentration was unaffected by the presence of DOC in the recycled wastewaters. This result indicates that these treated recycled wastewaters, because of their low DOC contents, will not affect B adsorption behavior of soils when used for irrigation of crops and landscape vegetation.

中文翻译：

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再生废水中溶解有机碳对土壤吸附硼的影响

摘要 在缺水地区，回收的市政废水被用作非饮用水应用的水资源，尤其是灌溉。此类废水通常含有较高水平的溶解有机碳 (DOC) 和溶液硼 (B)。作为平衡 B 浓度 (0-100 mg L-1) 和溶液 pH (4-10) 的函数，研究了来自加利福尼亚的 8 种干旱区土壤和来自亚利桑那州的一种土壤中的硼吸附。B 平衡溶液是使用回收的废水或含有高达 10 mg L-1 的 DOC 的合成废水制备的。合成废水被合成为具有与回收废水相同的化学成分，但不含 DOC。土壤对硼的吸附随着溶液 pH 值的增加而增加，在 pH 值 9 附近达到吸附峰，然后随着溶液 pH 值的进一步升高而降低。对于两种类型的水，在 95% 的置信水平下，pH 依赖的 B 吸附量在统计上没有显着差异。对于所有土壤，B 吸附作为溶液 B 浓度的函数符合朗缪尔吸附等温线方程。使用朗缪尔等温线获得的硼吸附最大值在 95% 置信水平下对于两种类型的水没有统计学上的显着差异。恒定电容表面络合模型能够使用土壤化学性质预测 B 吸附作为溶液 pH 值的函数：氧化铝、无机碳、有机碳含量和表面积。B 吸附量作为溶液 pH 值和平衡溶液 B 浓度的函数不受循环废水中 DOC 的影响。该结果表明，这些处理后的再生废水，由于其 DOC 含量低，当用于灌溉作物和景观植被时，不会影响土壤的 B 吸附行为。