Chong Mei Fong, Lee Kah Peng, Chieng Hui Jiun, Syazwani Binti Ramli Ili Izyan
School of Chemical Environmental Engineering, The University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor Darul Ehsan, Malaysia.
Water Res. 2009 Jul;43(13):3326-34. doi: 10.1016/j.watres.2009.04.044. Epub 2009 May 9.
Boron is extensively used in the ceramic industry for enhancing mechanical strength of the tiles. The discharge of boron containing wastewater to the environment causes severe pollution problems. Boron is also dangerous for human consumption and causes organisms' reproductive impediments if the safe intake level is exceeded. Current methods to remove boron include ion-exchange, membrane filtration, precipitation-coagulation, biological and chemical treatment. These methods are costly to remove boron from the wastewater and hence infeasible for industrial wastewater treatment. In the present research, adsorption-flocculation mechanism is proposed for boron removal from ceramic wastewater by using Palm Oil Mill Boiler (POMB) bottom ash and long chain polymer or flocculant. Ceramic wastewater is turbid and milky in color which contains 15 mg/L of boron and 2000 mg/L of suspended solids. The optimum operating conditions for boron adsorption on POMB bottom ash and flocculation using polymer were investigated in the present research. Adsorption isotherm of boron on bottom ash was also investigated to evaluate the adsorption capacity. Adsorption isotherm modeling was conducted based on Langmuir and Freundlich isotherms. The results show that coarse POMB bottom ash with particle size larger than 2 mm is a suitable adsorbent where boron is removed up to 80% under the optimum conditions (pH=8.0, dosage=40 g bottom ash/300 ml wastewater, residence time=1h). The results also show that KP 1200 B cationic polymer is effective in flocculating the suspended solids while AP 120 C anionic polymer is effective in flocculating the bottom ash. The combined cationic and anionic polymers are able to clarify the ceramic wastewater under the optimum conditions (dosage of KP 1200 B cationic polymer=100 mg/L, dosage of AP 120 C anionic polymer=50 mg/L, mixing speed=200 rpm). Under the optimum operating conditions, the boron and suspended solids concentration of the treated wastewater were reduced to 3 mg/L and 5 mg/L respectively, satisfying the discharge requirement by Malaysia Department of Environment (DOE). The modeling study shows that the adsorption isotherm of boron onto POMB bottom ash conformed to the Freundlich Isotherm. The proposed method is suitable for boron removal in ceramic wastewater especially in regions where POMB bottom ash is abundant.
硼在陶瓷工业中被广泛用于提高瓷砖的机械强度。含硼废水排放到环境中会造成严重的污染问题。硼对人体消费也有危害，如果超过安全摄入量，会导致生物体的生殖障碍。目前去除硼的方法包括离子交换、膜过滤、沉淀 - 混凝、生物和化学处理。这些方法从废水中去除硼成本高昂，因此对于工业废水处理来说不可行。在本研究中，提出了利用棕榈油厂锅炉（POMB）底灰和长链聚合物或絮凝剂从陶瓷废水中去除硼的吸附 - 絮凝机制。陶瓷废水浑浊且呈乳白色，含有15毫克/升的硼和2000毫克/升的悬浮固体。本研究考察了硼在POMB底灰上吸附以及使用聚合物进行絮凝的最佳操作条件。还研究了硼在底灰上的吸附等温线以评估吸附容量。基于朗缪尔和弗伦德利希等温线进行了吸附等温线建模。结果表明，粒径大于2毫米的粗POMB底灰是一种合适的吸附剂，在最佳条件下（pH = 8.0，用量 = 40克底灰/300毫升废水，停留时间 = 1小时）硼去除率可达80%。结果还表明，KP 1200 B阳离子聚合物在絮凝悬浮固体方面有效，而AP 120 C阴离子聚合物在絮凝底灰方面有效。阳离子和阴离子聚合物组合能够在最佳条件下（KP 1200 B阳离子聚合物用量 = 100毫克/升，AP 120 C阴离子聚合物用量 = 50毫克/升，混合速度 = 200转/分钟）澄清陶瓷废水。在最佳操作条件下，处理后废水的硼和悬浮固体浓度分别降至3毫克/升和5毫克/升，满足马来西亚环境部（DOE）的排放要求。建模研究表明，硼在POMB底灰上的吸附等温线符合弗伦德利希等温线。所提出的方法适用于陶瓷废水中硼的去除，特别是在POMB底灰丰富的地区。
