Abstract

This work presents report of the detoxification of cassava wastewater using bamboo (Bambusoideae) leaf. The aim of the detoxification process is toreduce the poisonous cyanide content to a permissible level of using cassava effluent for biogas production. Fresh leaves of bamboo and cassava roots used for this experiment were obtained from Enugu, Nigeria. The effluent was obtained from the cassava roots through grinding and dewatering processes, while fine particles of the bamboo leaf were obtained through sun-drying, grinding and sieving processes. Fourier transform infrared (FTIR) spectroscopy aided the determination of the functional groups characteristic to the substances which are present in bamboo leaf. Physicochemical properties of the cassava effluent (pH, BOD, COD and cyanide content) were evaluated. BOD tests were carried out by measuring the amount of dissolved oxygen present in the samples before and after incubation at 20°C for 5 days. Alkaline picrate method was used to determine the concentration of the cyanide. The cyanide content reduction was optimized using response surface methodology. It involved the use of central composite design of Design Expert software. The considered factors were particle size, mass/volume ratio, temperature and time while the response was cyanide content reduction. Analysis of variance (ANOVA) and mathematical modelling of the percentage removal of cyanide content were carried out. From the analysis of the results, the major functional groups responsible for the cyanide content removal werefound to be: C–H deformation, C=O stretching, C–H stretching, C=C=C stretching and O–H stretching. The presence of bamboo leaf reduced the cyanide content to 0.12 mg/L, a permissible level that is harmless to enzymatic reaction of biogas production. Quadratic model adequately described the percentage removal of the cyanide content. Optimum cyanide content removal of 83.6% was obtained at particle size of 0.458 mm, mass/volume ratio of 0.042 g/mL, temperature of 331.4 K, and time of 11.1 h. The model was confirmed by various criteria; correlation coefficient R² (0.9715), p value (<0.0001) and adequate precision (24.365).

中文翻译：

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竹叶在木薯废水解毒中潜在沼气的应用。

摘要

这项工作提出了使用竹子对木薯废水进行解毒的报告（竹节藻科） 叶子。排毒过程的目的是将使用木薯废水生产沼气的有毒氰​​化物含量降低到允许的水平。用于该实验的新鲜竹叶和木薯根叶购自尼日利亚埃努古。通过研磨和脱水过程从木薯根中获得废水，而通过晒干，研磨和筛分过程获得竹叶的细颗粒。傅里叶红外光谱（FTIR）有助于确定竹叶中所含物质的官能团。评估了木薯废水的理化性质（pH，BOD，COD和氰化物含量）。通过在20°C孵育5天之前和之后测量样品中存在的溶解氧的量来进行BOD测试。用碱性苦味酸盐法测定氰化物的浓度。使用响应表面方法优化了氰化物含量的降低。它涉及使用Design Expert软件的中央复合设计。考虑的因素是粒度，质量/体积比，温度和时间，而响应是氰化物含量降低。进行了方差分析（ANOVA）和氰化物含量去除百分率的数学模型。通过对结果的分析，发现负责氰化物含量去除的主要官能团为：C–H变形，C = O拉伸，C–H拉伸，C = C = C拉伸和OH–拉伸。竹叶的存在将氰化物的含量降低至0.12 mg / L，这是允许的水平，对沼气的酶促反应无害。二次模型充分描述了氰化物含量的去除百分比。在粒径为0.458 mm，质量/体积比为0.042 g / mL，温度为331.4 K，时间为11.1 h的条件下，最佳氰化物含量去除率为83.6％。该模型已通过各种标准得到确认；相关系数 该模型已通过各种标准得到确认；相关系数 该模型已通过各种标准得到确认；相关系数R ²（0.9715），p值（<0.0001）和足够的精度（24.365）。