PET 塑料的化学回收怎么做？
How does chemical recycling of PET work?
用糖解或甲醇解把聚酯水解/醇解回单体（BHET 或对苯二甲酸二甲酯），再聚合得到原生级塑料，可循环多次。
Glycolysis or methanolysis breaks the polyester back into monomers (BHET or DMT) that are repolymerized into virgin-grade plastic, recyclable many times.
难度 专业 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#PET #化学回收 #解聚
PETase 酶是怎么回事？
What is PETase?
从能降解塑料的细菌中发现的酶，可把 PET 水解成单体片段；比热解条件温和，是生物回收方向。
An enzyme found in plastic-degrading bacteria that hydrolyzes PET into monomer fragments; milder than pyrolysis, it points to biological recycling.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
Barnard et al., Green Chemistry, 2021, 23, 3765 (PET glycolysis review)
E. Barnard, J. J. Rubio Arias & W. Thielemans, Chemolytic depolymerisation of PET: a review, Green Chem., 2021, 23, 3765-3789
独立核验依据 · Independent verification: 核验依据 1 DOI 10.1039/d1gc00887k
#PETase #酶 #生物回收
机械回收和化学回收差在哪？
How do mechanical and chemical recycling differ?
机械回收熔融造粒、性能易下降；化学回收回到单体或油，质量接近原生但成本高、能耗大。
Mechanical recycling melts and pellets plastic, hurting properties; chemical recycling returns it to monomers or oil, near-virgin quality but costlier and energy-heavy.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#回收 #机械 #化学
可降解塑料真的能在土里消失吗，它和普通塑料有何不同？
Can biodegradable plastics really vanish in soil, and how do they differ?
像PHA、PLA这类塑料能被微生物当作碳源分解；但它们通常需要工业堆肥的高温条件，丢进普通环境并不一定能快速降解。
Plastics like PHA and PLA can be consumed by microbes, but they usually need industrial composting heat; in ordinary environments they may not break down quickly.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
邢其毅 等,《基础有机化学》第4版,北京大学出版社,2016
Xing Qiyi et al., Basic Organic Chemistry, 4th ed., Peking University Press, 2016
独立核验依据 · Independent verification: 核验依据 2 ISBN 9787301272121（豆瓣书目条目: 基础有机化学）
#可降解 #生物塑料 #微生物
PET的化学解聚回收中,甲醇醇解与糖酵解两条路线各得到什么单体?各自适合什么再生用途?
In chemical depolymerization recycling of PET, what monomers do methanolysis and glycolysis yield respectively, and what re-use routes suit each?
甲醇醇解在高温高压与催化剂作用下将PET打断为对苯二甲酸二甲酯(DMT)和乙二醇,产物经重结晶纯化后可直接重新缩聚制食品级PET。糖酵解则用乙二醇把PET降解为主要含对苯二甲酸双羟乙酯(BHET)及低聚物的混合物,提纯后同样回到聚合环节。糖酵解条件较温和、投资较低,适合中小规模处理有色瓶料,醇解产物更易精制,适合生产高纯度单体。
Methanolysis breaks PET into dimethyl terephthalate (DMT) and ethylene glycol at elevated temperature and pressure with a catalyst; after recrystallization the DMT can be repolymerized into food-grade PET. Glycolysis uses ethylene glycol to degrade PET mainly to bis(2-hydroxyethyl) terephthalate (BHET) plus oligomers, which are purified and fed back into polycondensation. Glycolysis runs under milder conditions with lower capital cost and suits colored bottle scrap at smaller scale, while methanolysis yields more easily refined monomers for high-purity applications.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-11-04
来源 · Source
Barnard 等,《Chemolytic depolymerisation of PET: a review》,Green Chemistry,2021 (DOI: 10.1039/d1gc00887k)
Barnard et al., 'Chemolytic depolymerisation of PET: a review', Green Chemistry, 2021, DOI: 10.1039/d1gc00887k
独立核验依据 · Independent verification: 核验依据 1 Crossref DOI 10.1039/d1gc00887k
#PET化学回收 #醇解
PET 饮料瓶化学回收中的糖酵解法与传统的机械回收相比有什么优势和局限?
What advantages and limitations does glycolysis offer for chemical recycling of PET bottles compared with conventional mechanical recycling?
糖酵解用过量乙二醇在催化剂作用下把 PET 解聚为对苯二甲酸双羟乙酯(BHET),可重新缩聚成原生级树脂,因此能处理含染料或多次回收降级的瓶片,实现闭环循环。机械回收仅熔融再加工,分子量下降且杂质累积限制使用次数。代价是能耗高、需要催化剂分离与纯化步骤,BHET 结晶纯化成本使整体经济性仍逊于成熟的大规模机械回收。
Glycolysis uses excess ethylene glycol with a catalyst to depolymerize PET into bis(2-hydroxyethyl) terephthalate (BHET), which can be re-polymerized into virgin-grade resin; this handles dyed or multi-cycle degraded flakes and closes the loop. Mechanical recycling merely remelts the polymer, where falling molecular weight and contaminant buildup limit reuse cycles. The trade-offs are higher energy demand plus catalyst separation and purification steps, and BHET crystallization costs keep overall economics behind mature large-scale mechanical recycling.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
Barnard et al., Green Chemistry, 2021, 23, 3765 (PET glycolysis review)
E. Barnard, J. J. Rubio Arias & W. Thielemans, Chemolytic depolymerisation of PET: a review, Green Chem., 2021, 23, 3765-3789
独立核验依据 · Independent verification: 核验依据 1 DOI 10.1039/d1gc00887k
#塑料化学回收 #PET 解聚
塑料瓶底的回收标号 1 到 7 号到底代表什么?为什么不混在一起回收?
What do recycling numbers 1 through 7 on plastics mean — and why not just mix them for recycling?
编号是美国塑料工业协会1988年定的树脂识别码:1号PET饮料瓶、2号HDPE洗涤剂瓶、3号PVC、4号LDPE薄膜、5号PP餐盒、6号PS泡沫、7号其他。分开回收是因为聚合物间相容性差,熔融共混时剧烈相分离;少量PVC混入PET回收流受热会分解出盐酸,腐蚀设备并黄化整批料,故回收厂以红外光谱按号分选后再清洗造粒。工程上也可有意借增容剂做PC/ABS等合金,但那是精密配方,不是垃圾场里的偶遇。
The codes are a 1988 resin identification system: 1 PET bottles, 2 HDPE jugs, 3 PVC, 4 LDPE film, 5 PP tubs, 6 PS foam, 7 others. Separation matters because unlike polymers mix like oil and water — molten blends phase-separate badly, and even trace PVC in a PET stream releases hydrochloric acid that corrodes equipment and yellows the batch. Facilities therefore sort by infrared spectroscopy before washing, shredding and pelletizing each stream. Intentional blending exists — compatibilized engineering alloys like PC/ABS — but those are precise recipes, not landfill luck.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-11-02
来源 · Source
Andrady 主编,《Plastics and the Environment»,Wiley,2003
A. L. Andrady ed., Plastics and the Environment, Wiley, 2003
独立核验依据 · Independent verification: 核验依据 1 OPENLIBRARY 标识 /works/OL8225218W：Plastics and the enviro
#树脂识别码 #聚合物相容性 #分选
塑料瓶底的三角数字（1到7）是什么意思？
What do the triangle numbers 1–7 on plastic bottles mean?
那是树脂识别码，标明塑料种类，比如1是PET、2是HDPE，方便分类回收，但不等于保证能回收。
They are resin identification codes labeling the polymer type (1=PET, 2=HDPE), aiding sorting—not a guarantee of recyclability.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
邢其毅 等,《基础有机化学》第4版,北京大学出版社,2016
Xing Qiyi et al., Basic Organic Chemistry, 4th ed., Peking University Press, 2016
独立核验依据 · Independent verification: 核验依据 2 ISBN 9787301272121（豆瓣书目条目: 基础有机化学）
#回收 #塑料 #分类